Photonic crystal optical filter, preparation method of photonic crystal optical filter, spectrum detection system and spectrum detection method

Abstract

The invention discloses a photonic crystal optical filter and a preparation method thereof, and a spectrum detection system and method, and the photonic crystal optical filter comprises a photonic crystal part which comprises a plurality of photonic crystal units, each photonic crystal unit comprises a plurality of through holes arranged in an array, each photonic crystal unit comprises a central region and a peripheral region, the plurality of through holes comprise a first through hole in the central area and a second through hole in the peripheral area; the central area comprises Na * Na first through holes, and Na is a positive integer greater than or equal to 5; the number of the second through holes in each edge of the peripheral area is Na * Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between every two adjacent first through holes is a first distance Da, the minimum distance between every two adjacent second through holes is a second distance Db, the minimum distance between the first through holes and the second through holes is a third distance Dg, Na * Da + Nb * Db + Dg is smaller than or equal to 10 micrometers, and the spectrum detection system has the advantages of being high in detection precision, small in structural size, stable in structure and the like.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a photonic crystal filter, a method for preparing the photonic crystal filter, a spectrum detection system, and a spectrum detection method. Background Art

[0002] Spectroscopy is an important method for characterizing the spectral features of light, which can be used in fields such as agriculture, medicine and communications. Micro-spectrometers have become an emerging field due to their unique ability to be portable and for on-site diagnostics, and major advances have been made through the use of dispersive or narrow-band optical elements and Fourier transform devices. In principle, photons can be spectrally distinguished by sufficiently different optical paths or lifetimes. Achieving the optimal size, resolution and range in a micro-spectrometer requires a complex trade-off, as limited volume limits the ability to extend the optical path, while narrow-band resonances make it difficult to cover the entire required spectrum.

[0003] However, highly spectrally selective components, such as high-quality (Q) optical resonators, are essential and highly advantageous for achieving high resolution. By arranging high-Q resonators into arrays, the detection range can be extended while maintaining compact size using state-of-the-art nanofabrication techniques. Therefore, various miniaturized resonators such as nanowires, quantum dots, microring resonators, and plasmonic metasurfaces have been used for parallel spectral detection. However, most resonant structures that can produce high Q values ​​require symmetry. When preparing fine structures, electron beam lithography (EBL) technology is required. When the resonant unit is larger than the EBL writing field size, there are often mechanical errors, beam drifting, and other problems that lead to performance degradation. Therefore, miniaturization of device size is necessary. However, to achieve high resolution and wide detection range, the resonator array must be large-scale, which poses great challenges to connecting, scanning, and calibrating the components. Therefore, ultra-high-Q microcavities capable of out-of-plane excitation may be a promising candidate because they can avoid the need for planar coupling and time scanning like microring resonator arrays. Therefore, it is a challenging problem to design a high-Q microcavity array with a unit volume as small as possible while improving the spectral detection performance. Summary of the invention

[0004] At least one embodiment of the present disclosure provides a photonic crystal filter, a method for preparing the photonic crystal filter, a spectral detection system and a spectral detection method. The photonic crystal filter has a narrowband filtering capability by precisely designing the photonic crystal portion, thereby realizing efficient filtering of light of a specific wavelength, and the filtering capability of the photonic crystal filter and the wavelength of the light that can be filtered can be adjusted according to the precise design. When the photonic crystal filter is applied to the spectral detection system, spectral detection can be realized and the accuracy of spectral detection can be improved. Moreover, the spectral detection system and spectral detection method provided by the embodiments of the present disclosure can achieve the advantages of process robustness, high accuracy, adjustable accuracy and smaller size through simple arraying, which is conducive to further realizing a miniaturized spectral detection system.

[0005] At least one embodiment of the present disclosure provides a photonic crystal filter, which includes: a photonic crystal portion, wherein the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each of the photonic crystal units includes a plurality of through holes arranged in an array, each of the photonic crystal units includes a central area and a peripheral area surrounding the central area, the plurality of through holes include first through holes arranged in an array in the central area and second through holes arranged in an array in the peripheral area; the central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of the second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between the first through hole and the second through hole is a third spacing Dg, and satisfies Na*Da+Nb*Db+Dg≤10μm.

[0006] For example, in the photonic crystal filter provided in at least one embodiment of the present disclosure, the minimum distance between two adjacent photonic crystal units is a fourth spacing Nag, and the fourth spacing Nag is greater than or equal to 5 microns and less than or equal to 10 microns.

[0007] For example, in the photonic crystal filter provided in at least one embodiment of the present disclosure, a transition area is further included between the central area and the peripheral area, the through holes further include third through holes arranged in an array in the transition area, the minimum distance between any two adjacent third through holes is the fifth spacing, the arrangement density of the first through holes is greater than the arrangement density of the third through holes, and the arrangement density of the third through holes is greater than the arrangement density of the second through holes, the first spacing is less than the fifth spacing, and the fifth spacing is less than the second spacing; or, the arrangement density of the first through holes is less than the arrangement density of the third through holes, and the arrangement density of the third through holes is less than the arrangement density of the second through holes, the first spacing is greater than the fifth spacing, and the fifth spacing is greater than the second spacing.

[0008] For example, in the photonic crystal filter provided in at least one embodiment of the present disclosure, the planar shapes of the first through hole, the second through hole and the third through hole are the same, the planar size of the first through hole is smaller than the planar size of the second through hole, and the planar size of the second through hole is smaller than the planar size of the third through hole.

[0009] For example, in the photonic crystal filter provided in at least one embodiment of the present disclosure, the first through holes are arranged in a matrix, and the overall outer contour shape of the first through holes arranged in a matrix is ​​a quadrilateral, and the second through holes are arranged on one side of each side of the quadrilateral away from the center of the central area, and the second through holes surround the entire first through holes arranged in a matrix.

[0010] For example, in the photonic crystal filter provided in at least one embodiment of the present disclosure, the rectangular array formed by the first through holes is a square array, and the planar shape of the central area is a square; the peripheral area includes four side areas and four corner areas, and the shapes of the four side areas and the four corner areas are all rectangular; the long sides of each of the four side areas close to the central area are aligned with the four sides of the central area and are of equal length; the four corner areas are respectively located at the four corners of the central area in the direction away from the center of the square, and the two adjacent sides of each of the four corner areas are aligned with the short sides of the two adjacent side areas close to it and are of equal length.

[0011] For example, in the photonic crystal filter provided in at least one embodiment of the present disclosure, the four side regions are all rectangular regions formed by Na×Nb second through holes, and the four corner regions are all square regions formed by Nb×Nb second through holes, and Na and Nb are both positive integers.

[0012] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure further includes an active layer and a first dielectric layer disposed between the active layer and the photonic crystal portion, wherein the active layer is configured to emit light and serve as an optical gain medium.

[0013] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure also includes a second dielectric layer arranged on a side of the photonic crystal portion away from the first dielectric layer, wherein each of the through holes includes a first end and a second end opposite to each other along the extension direction of its channel, the first end is connected to the first dielectric layer, and the second end is connected to the second dielectric layer.

[0014] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure also includes: an n-type substrate; an n-type semiconductor heavily doped layer and an n-type semiconductor doped layer sequentially arranged on the n-type substrate; a p-type semiconductor doped layer and a p-type semiconductor heavily doped layer sequentially arranged on a side of the active layer away from the n-type substrate; a p-type electrode layer arranged on a side of the p-type semiconductor heavily doped layer away from the n-type substrate; and an n-type electrode layer arranged on a side of the n-type semiconductor heavily doped layer away from the n-type substrate and spaced from the n-type semiconductor doped layer; wherein the active layer is arranged on a side of the n-type semiconductor doped layer away from the n-type substrate; the p-type semiconductor heavily doped layer is configured as the second dielectric layer; and the p-type semiconductor doped layer is configured as the photonic crystal portion and the first dielectric layer.

[0015] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure also includes: an n-type substrate; an n-type semiconductor heavily doped layer and an n-type semiconductor doped layer sequentially arranged on the n-type substrate; a p-type semiconductor doped layer and a p-type semiconductor heavily doped layer sequentially arranged on a side of the active layer away from the n-type substrate; a p-type electrode layer arranged on a side of the p-type semiconductor heavily doped layer away from the n-type substrate, and an n-type electrode layer arranged on a side of the n-type semiconductor heavily doped layer away from the n-type substrate and spaced from the n-type semiconductor doped layer; wherein the active layer is arranged on a side of the n-type semiconductor doped layer away from the n-type substrate; the n-type semiconductor heavily doped layer is configured as the second dielectric layer; and the n-type semiconductor doped layer is configured as the photonic crystal portion and the first dielectric layer.

[0016] At least one embodiment of the present disclosure also provides a method for preparing a photonic crystal filter, the method comprising: providing a substrate; forming a first type of semiconductor doped layer thin film on the substrate; applying a resist on the first type of semiconductor doped layer thin film, and pre-curing it to form a resist layer; using an imprint template to perform nano-imprinting on the resist layer to transfer the pattern of the imprint template to the resist layer, and curing it to form a resist layer pattern; using the resist layer pattern as a mask to perform a composition process on the first type of semiconductor doped layer thin film to form a photonic crystal layer, and removing the resist layer pattern; wherein the photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each of the photonic crystal units The photonic crystal unit comprises a plurality of through holes arranged in an array, each of the photonic crystal units comprises a central area and a peripheral area surrounding the central area, the plurality of through holes comprises first through holes arranged in an array in the central area and second through holes arranged in an array in the peripheral area; the central area comprises Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of the second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between the first through hole and the second through hole is a third spacing Dg, and satisfies Na*Da+Nb*Db+Dg≤10μm.

[0017] For example, the preparation method provided by at least one embodiment of the present disclosure also includes: forming an active layer film on the substrate; forming a first dielectric layer film between the active layer film and the photonic crystal layer; wherein the active layer film is configured to emit light and serve as an optical gain medium.

[0018] For example, the preparation method provided by at least one embodiment of the present disclosure also includes forming a second dielectric layer film on a side of the photonic crystal layer away from the first dielectric layer film, wherein the material of the second dielectric layer film is a heavily doped material of a first type of semiconductor, and each of the through holes includes a first end and a second end opposite to each other along the extension direction of its channel, the first end is connected to the first dielectric layer film, and the second end is connected to the second dielectric layer film.

[0019] At least one embodiment of the present disclosure further provides a spectral detection system, which includes: a semi-transparent and semi-reflective mirror, an objective lens, an imaging structure, a 4f optical system, and the photonic crystal filter described in any of the above embodiments.

[0020] At least one embodiment of the present disclosure further provides a spectral detection method, which comprises: forming spectra to be measured with different characteristics; inputting the spectra to be measured into any of the spectral detection systems described above to distinguish the spectra to be measured with different characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure.

[0022] Figure 1 A block diagram of a photonic crystal filter is provided for at least one embodiment of the present disclosure;

[0023] Figure 2 A schematic diagram of a planar structure of a photonic crystal portion provided by at least one embodiment of the present disclosure;

[0024] Figure 3 for Figure 2 A schematic diagram of the local enlarged structure of the middle area of ​​the photonic crystal part;

[0025] Figure 4 A schematic diagram of a planar structure of another photonic crystal portion provided in at least one embodiment of the present disclosure;

[0026] Figure 5 for Figure 4 A schematic diagram of the enlarged structure of the area B defined by the dotted line in FIG.

[0027] Figure 6 A schematic diagram of a planar structure of another photonic crystal portion provided for at least one embodiment of the present disclosure;

[0028] Figure 7 for Figure 6 A schematic diagram of the enlarged structure of the area C defined by the middle dotted line;

[0029] Figure 8 A schematic diagram of a planar structure of another photonic crystal portion provided for at least one embodiment of the present disclosure;

[0030] Fig. 9 for Figure 8 A schematic diagram of the enlarged structure of the area D defined by the middle dotted line;

[0031] Fig.10 A schematic diagram of a planar structure of another photonic crystal portion provided for at least one embodiment of the present disclosure;

[0032] Fig.11 A schematic diagram of a planar structure of a plurality of photonic crystal portions arranged in an array and an enlarged structure of a single photonic crystal portion provided in at least one embodiment of the present disclosure;

[0033] Fig.12 A schematic diagram of the cross-sectional structure of a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0034] Fig.13 A schematic diagram of the cross-sectional structure of yet another photonic crystal filter provided in at least one embodiment of the present disclosure;

[0035] Fig.14 A flow chart of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0036] Figures 15A-15E A process diagram of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0037] Fig.16 A flow chart of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0038] Figures 17A-17H A process diagram of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0039] Fig.18 A flow chart of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0040] Figures 19A-19I A process diagram of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0041] Fig. 20 A block diagram of a spectral detection system provided for at least one embodiment of the present disclosure;

[0042] Fig.21 A pattern of a photonic crystal microcavity array measured by a spectrum testing system having a photonic crystal filter according to at least one embodiment of the present disclosure;

[0043] Fig. 22 A loss curve diagram of a demodulated spectral neural network training process provided by at least one embodiment of the present disclosure;

[0044] Fig.23 A demodulation spectrum performance characterization diagram provided for at least one embodiment of the present disclosure; and

[0045] Fig.24 A simulation performance diagram of a spectral detection system for avoiding the write field splicing problem provided by at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0047] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0048] The photonic crystal filter has the advantages of high power, high reliability, long life, small size, high quality factor, small divergence angle, narrow spectral line width, suitability for multi-wavelength single-mode operation and low cost, and is used in various fields. For example, the inventors of the present disclosure noticed that in the field of spectral detection, the photonic crystal part included in the spectral detection system usually has a regular shape unit, the size of the photonic crystal part can be smaller than the sub-writing field size of the commonly used electron beam exposure, each regular shape unit has a variety of frequency selection capabilities at different wavelengths, the frequency selection capability can be adjusted according to the required spectral recovery accuracy, and the wavelengths corresponding to the characteristic frequencies of adjacent units are uncorrelated, so that the coupling between adjacent units due to the similar wavelengths can be effectively avoided.

[0049] The inventors of the present disclosure also noticed that based on the structure of the photonic crystal filter, the spectral detection system and the spectral detection method, the pattern of the structure to be detected can be detected through an optical path based on the 4f optical system. In addition, rich patterns can be generated in an extremely small array unit volume, which represents the corresponding high-Q resonance peaks of different characteristic wavelengths generated by the structure to be detected, thereby realizing the detection of the spectrum to be detected.

[0050] For example, Figure 1 A block diagram of a photonic crystal filter is provided for at least one embodiment of the present disclosure, such as Figure 1The photonic crystal filter 10 comprises a photonic crystal part 100. The working principle of the photonic crystal part 100 is: in the photonic crystal part 100, an optical bandgap structure is generated due to the periodic change of the refractive index of light, so that the movement of light in the photonic crystal part is controlled by the optical bandgap structure, that is, the photonic crystal part periodically has a low refractive index at certain positions of the high refractive index material. The photonic crystal bandgap (BandGap, similar to the forbidden band in semiconductors) can be generated by alternating the high refractive index material and the low refractive index material to form a periodic structure, and the distances between the periodically arranged low refractive index sites are the same, resulting in the photonic crystal part with a certain distance only producing a band effect for light waves of a certain frequency, that is, only light of a certain frequency will be completely prohibited from propagating in a photonic crystal with a certain periodic distance.

[0051] For example, Figure 2 A schematic diagram of a planar structure of a photonic crystal portion provided in at least one embodiment of the present disclosure is shown in FIG. Figure 2 As shown, the photonic crystal portion 100 includes a plurality of photonic crystal units arranged in an array, and each photonic crystal unit includes a plurality of through holes 101 arranged in an array. Figure 2 In the example, the plane shape of each through hole 101 is a circle. Figure 2 In the embodiment of the present disclosure, the diameter of each circle is equal, that is, the plane size of each through hole 101 is equal. Of course, the embodiment of the present disclosure is not limited to this, and the plane shape of each through hole 101 can also be an ellipse, a triangle, a regular hexagon, an irregular shape or a combination of multiple shapes. The embodiment of the present disclosure is not limited to this, as long as the through holes 101 can be arranged in an array and can be easily formed by nanoimprinting.

[0052] It should be noted that when the planar shape of the through hole 101 is circular, the pattern that the imprint template used in the nanoimprint process can imprint is circular; when the planar shape of the through hole 101 is triangular, the pattern that the imprint template used in the nanoimprint process can imprint is triangular; when the planar shape of the through hole 101 is elliptical, the pattern that the imprint template used in the nanoimprint process can imprint is elliptical; when the planar shape of the through hole 101 is a regular hexagon, the pattern that the imprint template used in the nanoimprint process can imprint is a regular hexagon, that is, according to the different planar shapes of the through holes 101 formed, the shapes of the patterns that can be imprinted by the selected nanoimprint template are different. For example, in the same photonic crystal part, a part of the through hole 101 and another part of the through hole 101 can also have different planar shapes, or different planar sizes. In the embodiments of the present disclosure, it is only necessary to select a suitable nanoimprint template according to the pattern of the through hole to be formed, and there are many types of nanoimprint templates, which can easily meet different pattern requirements. The cost of the nanoimprint template is low, and the photonic crystal part with through holes of different plane shapes or different plane sizes is formed in only one imprint process, and other process conditions remain unchanged. However, for the commonly used electron beam exposure process, the exposure time is long, which will reduce work efficiency and increase production costs.

[0053] For example, Figure 2 In the description, the shape of each through hole 101 is cylindrical, the plane shape of each through hole 101 is circular, and the diameter of each circle is the same. In one example, along the extension direction of each through hole 101, the size of each through hole 101 is equal or approximately equal. The following description mainly takes the plane shape of the through holes 101 as an example.

[0054] For example, in other examples, the shape of the through hole 101 may also be an elliptical cylinder, that is, the plane shape of each through hole 101 is an ellipse, and the major axis and minor axis of each ellipse are equal; the shape of the through hole 101 may also be a triangular prism, that is, the plane shape of each through hole 101 is a triangle, and the three sides of any two triangles are respectively equal. Of course, in other embodiments, the through hole 101 may also have other shapes, and the embodiments of the present disclosure are not limited to this.

[0055] For example, Figure 2 As shown, each photonic crystal unit includes a central region 102 and a peripheral region 103 surrounding the central region 102. For example, Figure 2In the figure, the planar shapes of the central region 102 and the peripheral region 103 are both rectangles. The through hole 101 in the peripheral region 103 only surrounds the four side regions of the through hole 101 in the central region 102, and does not surround the corner regions. Of course, the embodiments of the present disclosure are not limited to this, and the central region 102 may also be surrounded at the corner regions, or the overall shape of the peripheral region 103 may not be a plurality of rectangles, but may be a circular ring, a square ring, an ellipse, etc., as long as the energy of the central region 102 of the photonic crystal portion can be suppressed from leaking from the peripheral region 103 or the energy of the central region 102 of the photonic crystal portion can be controlled to radiate to the peripheral region 103.

[0056] For example, the peripheral region 103 is used to control and suppress the energy leakage of the central region 102 or control the energy of the central region 102 to radiate toward the peripheral region 103, so as to achieve the frequency selection capability of the photonic crystal unit.

[0057] For example, Figure 2 As shown, the plurality of through holes 101 include first through holes 101a arranged in an array in a central region 102 and second through holes 101b arranged in an array in a peripheral region 103. The relative arrangement density of the first through holes 101a is different from the relative arrangement density of the second through holes 101b. Figure 2 In the embodiment, the relative arrangement density of the first through holes 101a is greater than the relative arrangement density of the second through holes 101b.

[0058] For example, Figure 3 for Figure 2 The enlarged structural diagram of the dotted line-limited area A is shown in FIG. Figure 3 As shown, the first through holes 101a are formed by nanoimprinting, and the first through holes 101a are arranged in a matrix, that is, the first through holes 101a are arranged in the X-axis direction and the Y-axis direction, and the plane defined by the X-axis and the Y-axis is the plane where the top surface of the first through hole 101a is located, and the direction perpendicular to the plane defined by the X-axis and the Y-axis is the thickness direction of the photonic crystal filter, that is, the extension direction of the through hole 101. The dotted line defines the area A including the first through hole 101a and the second through hole 101b, as shown in FIG. Figure 3 As shown, the minimum distance between any two adjacent first through holes 101a is the first spacing Da. It should be noted that the minimum distance between any two adjacent first through holes 101a means that any two adjacent first through holes 101a have different sizes along different directions, and the smallest size among these different sizes is the minimum distance between any two adjacent first through holes 101a. Figure 3In the embodiment, the distance between two adjacent first through holes 101a in the first direction X is smaller than the distance between two adjacent first through holes 101a in the second direction Y, that is, the minimum distance between two adjacent first through holes 101a in the first direction X is Da.

[0059] For example, in Figure 3 In the example, the minimum distance between any two adjacent second through holes 101b is the second spacing Db. Similarly, the minimum distance between any two adjacent second through holes 101b means that any two adjacent second through holes 101b have different sizes along different directions, and the smallest size among these different sizes is the minimum distance between any two adjacent second through holes 101b. Figure 3 In the embodiment, the distance between two adjacent second through holes 101b in the second direction Y is smaller than the distance between two adjacent second through holes 101b in the first direction X, that is, the distance between two adjacent second through holes 101b in the second direction Y is at least Db, and Figure 3 In the embodiment, the relative arrangement density of the first through holes 101a is greater than the relative arrangement density of the second through holes 101b, and the first interval Da is smaller than the second interval Db.

[0060] For example, in Figure 3 In the left dashed box, the first through holes 101a and Figure 3 A row of second through holes 101b close to the left side in the dotted box on the right are arranged adjacent to each other, and the minimum distance between any adjacent first through holes 101a and second through holes 101b is a third spacing Dg, which is greater than the first spacing Da and less than the second spacing Db, that is, along the direction from the peripheral area 103 to the central area 102, the minimum distance between adjacent first through holes 101a, the minimum distance between adjacent first through holes 101a and second through holes 101b, and the minimum distance between adjacent second through holes 101b gradually decrease.

[0061] It should be noted that in Figure 3 In other variations, in the first direction X, along the direction from the peripheral area 103 to the central area 102, the spacing between adjacent first through holes 101a gradually decreases, and the spacing between adjacent second through holes 101b also gradually decreases, so that in the first direction X, along the direction from the peripheral area 103 to the central area 102, the distance between adjacent through holes 101 (including the first through holes 101a and the second through holes 101b) gradually decreases.

[0062] Specifically, combined Figure 2 and Figure 3, the central area 102 includes Na×Na first through holes 101a, wherein Na is a positive integer greater than or equal to 5; the number of second through holes 101b on each side of the peripheral area 103 is Na*Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes 101a is the first spacing Da, the minimum distance between two adjacent second through holes 101b is the second spacing Db, the minimum distance between the first through hole and the second through hole is the third spacing Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied, wherein, in the peripheral areas on the left and right sides, Nb is the number of columns of the second through holes 101b in the peripheral area 103; in the peripheral areas on the upper and lower sides, Nb is the number of rows of the second through holes 101b in the peripheral area 103. That is, the above-mentioned Na, Nb, first spacing Da, second spacing Db and third spacing Dg in the central area of ​​the photonic crystal part prepared by the nanoimprinting method in the embodiment of the present invention are fluctuating. Under the conditions limited by the above data, it is possible to use nanoimprinting technology to prepare the photonic crystal part on the basis of ensuring high robustness and high quality factor (Q value), so as to reduce production costs and improve production efficiency, and it is suitable for large-scale production. When it is applied to the spectral detection system, it can improve the accuracy and efficiency of spectral detection.

[0063] For example, since the photonic crystal filter provided by the embodiments of the present disclosure has a fine structure, when Na, Da, Nb, Db, and Dg satisfy the above relationship, it is still necessary to finely design the structural parameters to achieve the desired optical properties. Specific geometric parameters (such as lattice constant and aperture) determine the position and width of the photonic band gap, and these parameters can also be finely adjusted to satisfy certain relationships to form the desired resonance characteristics.

[0064] For example, by optimizing the above structural parameters, a resonant mode with a high quality factor (Q value) and narrow linewidth can be obtained, which is essential for achieving efficient optical field confinement and low-loss transmission, and can improve the coherence of the photonic crystal filter, reduce the threshold power, and improve the overall performance of the photonic crystal filter. At the same time, the fine design of the photonic crystal filter can ensure that the subsequent spectral detection system has stable working characteristics near the target wavelength, making the spectral detection system more reliable in practical applications.

[0065] The embodiments of the present disclosure require the careful design of multiple parameters, thereby increasing the complexity of the design process. It is necessary to consider the relationship between multiple variables and accurately control them so that the photonic band gap and the resonant wavelength fall within the target range. Generally, the structural design of the through holes in the photonic crystal filter requires nanometer-level processing accuracy, and involves multiple simulations and experimental iterations to verify the rationality of the design. In addition, due to the limitations of processing equipment and process conditions, the problem of error accumulation may be encountered in actual production, which will affect the design accuracy of the photonic crystal filter. Therefore, the design of the photonic crystal filter must not only meet the theoretical requirements, but also take into account the feasibility of the processing technology, which further increases the design difficulty and challenges.

[0066] For example, in one example, the number of photonic crystal units arranged in an array is 400, the value range of the first spacing Da is 522nm~540nm, the value range of the second spacing Db is 552nm~570nm, the value range of the third spacing Dg is 532nm~550nm, the above Na value is 7, and the above Nb value is 6.

[0067] For example, Figure 4 A schematic diagram of a planar structure of another photonic crystal portion provided in at least one embodiment of the present disclosure is shown in FIG. Figure 4 As shown, the photonic crystal portion 100 includes a central region 102 and a peripheral region 103 surrounding the central region 102. For example, Figure 4 The central area 102 and the peripheral area 103 are both rectangular in plan view. The through hole 101 in the peripheral area 103 only surrounds the four side areas of the through hole 101 in the central area 102, but not the corner areas. Figure 4 In the embodiment, the plurality of through holes 101 include first through holes 101a arranged in an array in a central region 102 and second through holes 101b arranged in an array in a peripheral region 103, and a relative arrangement density of the first through holes 101a is less than a relative arrangement density of the second through holes 101b.

[0068] It should be noted that when the planar shape and planar size of the first through hole 101a and the second through hole 101b are the same, the relative arrangement density of the first through holes 101a refers to the number of first through holes 101a per unit area, and the relative arrangement density of the second through holes 101b refers to the number of second through holes 101b per unit area. When the shapes or sizes of the first through hole 101a and the second through hole 101b are different, an equivalent conversion is performed based on the plane areas of the first through hole 101a and the second through hole 101b. For example, when the plane area of ​​one first through hole 101a is equivalent to the plane area of ​​two second through holes 101b, the relative arrangement density of the first through holes 101a refers to twice the number of first through holes 101a per unit area, and the relative arrangement density of the second through holes 101b refers to the number of second through holes 101b per unit area; or, when the plane area of ​​one first through hole 101a is equivalent to 0.5 of the plane area of ​​the second through holes 101b, the relative arrangement density of the first through holes 101a refers to the number of first through holes 101a per unit area, and the relative arrangement density of the second through holes 101b refers to twice the number of second through holes 101b per unit area. That is, when the planar area of ​​a first through hole 101a is equivalent to the planar area of ​​n second through holes 101b, and n is greater than 1, the relative arrangement density of the first through holes 101a refers to n times the number of first through holes 101a per unit area, and the relative arrangement density of the second through holes 101b refers to the number of second through holes 101b per unit area; when n is greater than 0 and less than 1, when the planar area of ​​a first through hole 101a is equivalent to the planar area of ​​n second through holes 101b, the relative arrangement density of the first through holes 101a refers to the number of first through holes 101a per unit area, and the relative arrangement density of the second through holes 101b refers to 1 / n times the number of second through holes 101b per unit area.

[0069] For example, in one example, although Figure 2 and Figure 4 The relative arrangement densities of the first through holes 101a and the second through holes 101b are different. Figure 2 and Figure 4 The first through hole 101a and the second through hole 101b in the nanostructured substrate can also be completed in the same nanoimprint process step without increasing the production cost.

[0070] For example, Figure 5 for Figure 4 FIG. 1 is a schematic diagram of an enlarged structure of a dotted line defined region B in FIG. 1 , wherein the dotted line defined region B includes a first through hole 101a and a second through hole 101b. Figure 5As shown, the minimum distance between any two adjacent first through holes 101a is the first spacing Da. It should be noted that the minimum distance between any two adjacent first through holes 101a means that any two adjacent first through holes 101a have different sizes along different directions, and the smallest size among these different sizes is the minimum distance between any two adjacent first through holes 101a. Figure 5 In the embodiment, the distance between two adjacent first through holes 101a in the first direction X is smaller than the distance between two adjacent first through holes 101a in the second direction Y, that is, the minimum distance between two adjacent first through holes 101a in the first direction X is Da.

[0071] For example, in Figure 5 In the example, the minimum distance between any two adjacent second through holes 101b is the second spacing Db. Similarly, the minimum distance between any two adjacent second through holes 101b means that any two adjacent second through holes 101b have different sizes along different directions, and the smallest size among these different sizes is the minimum distance between any two adjacent second through holes 101b. Figure 5 In the embodiment, the distance between two adjacent second through holes 101b in the second direction Y is smaller than the distance between two adjacent second through holes 101b in the first direction X, that is, the minimum distance between two adjacent second through holes 101b in the second direction Y is Db, and Figure 5 In the embodiment, the relative arrangement density of the first through holes 101a is less than the relative arrangement density of the second through holes 101b, and the first interval Da is greater than the second interval Db.

[0072] For example, in Figure 5 In the left dashed box, the second through holes 101b and Figure 5 The first through holes 101a in a row near the left side in the dotted box on the right are arranged adjacent to each other, and the minimum distance between any adjacent first through holes 101a and second through holes 101b is a third spacing Dg, which is greater than the second spacing Db and less than the first spacing Da.

[0073] For example, in Figure 5 In the figure, the first spacing Da is the spacing in the first direction X, the second spacing Db is the spacing in the second direction Y, and the third spacing Dg is a direction on the plane formed by the first direction X and the second direction Y that has a certain angle with the first direction and the second direction, and the direction is determined according to the arrangement of the adjacent first through holes 101a and the second through holes 101b.

[0074] It should be noted that in Figure 5In other variations, the spacing between adjacent first through holes 101a may be gradually increased along the direction from the peripheral area 103 to the central area 102 in the first direction X, and the spacing between adjacent second through holes 101b may also be gradually increased. Except that the distance between adjacent first through holes 101a and second through holes 101b is not along the direction from the peripheral area 103 to the central area 102, the spacing between other adjacent through holes 101 may be the spacing along the direction from the peripheral area 103 to the central area 102 in the first direction X, that is, Figure 5 Without considering the adjacent first through hole 101 a and the second through hole 101 b , along the direction from the peripheral area 103 to the central area 102 , the spacing between other adjacent through holes 101 may be gradually increased.

[0075] For example, Figure 6 A schematic diagram of a planar structure of another photonic crystal portion provided in at least one embodiment of the present disclosure is shown in FIG. Figure 6 As shown, the photonic crystal portion 100 includes a central region 102, a peripheral region 103 surrounding the central region 102, and a transition region 104 between the central region 102 and the peripheral region 103. For example, Figure 6 The central area 102, the transition area 104 and the peripheral area 103 are all rectangular in planar shape. The through hole 101 in the peripheral area 103 only surrounds the four side areas of the through hole in the central area 102, and does not surround the corner area. Of course, the embodiment of the present disclosure is not limited to this, and the central area can also be surrounded at the corner area.

[0076] For example, Figure 7 for Figure 6 The enlarged structural diagram of the area C defined by the dashed line, combined with Figure 6 and Figure 7 , the through hole 101 further includes third through holes 101c arranged in an array in the transition region 104, the minimum distance between any two adjacent third through holes 101c is the fifth spacing d5, the minimum distance between any two adjacent first through holes 101a is the first spacing Da, and the minimum distance between any two adjacent second through holes 101b is the second spacing Db. For example, in Figure 6 and Figure 7 In the embodiment, the relative arrangement density of the first through holes 101a is greater than the relative arrangement density of the second through holes 101b, the relative arrangement density of the third through holes 101c is greater than the relative arrangement density of the second through holes 101b and less than the relative arrangement density of the first through holes 101a, the first spacing Da is less than the fifth spacing d5, and the fifth spacing d5 is less than the second spacing Db.

[0077] For example, Figure 7As shown, the minimum distance between the adjacent third through holes 101c and the first through holes 101a is the sixth spacing d6, and the minimum distance between the adjacent third through holes 101c and the second through holes 101b is the seventh spacing d7. The sixth spacing d6 is smaller than the fifth spacing d5 and larger than the first spacing Da, and the seventh spacing d7 is larger than the fifth spacing d5 and smaller than the second spacing Db. This arrangement enables the peripheral area and the transition area to fully wrap the central area. The periodicity of the third through holes 101c in the transition area arranged in the middle, the periodicity of the second through holes 101b in the peripheral area, and the periodicity of the first through holes 101a in the central area 102 are all different, so that the transition area further blocks the energy leakage or radiation in the two-dimensional photonic crystal microcavity, so as to more fully suppress the energy leakage in the two-dimensional photonic crystal microcavity from the peripheral area or control the energy in the two-dimensional photonic crystal microcavity to radiate to the peripheral area. Moreover, this arrangement can also improve the robustness.

[0078] For example, setting the distance between the third through holes 101c in the transition area to the above size range can meet the application requirements of different scenarios.

[0079] For example, Figure 8 A schematic diagram of a planar structure of another photonic crystal portion provided in at least one embodiment of the present disclosure is shown in FIG. Figure 8 As shown, the photonic crystal portion 100 includes a central region 102, a peripheral region 103 surrounding the central region 102, and a transition region 104 between the central region 102 and the peripheral region 103. For example, Figure 8 The central area 102, the transition area 104 and the peripheral area 103 are all rectangular in planar shape. The through hole 101 in the peripheral area 103 only surrounds the four side areas of the through hole in the central area 102, and does not surround the corner area. Of course, the embodiment of the present disclosure is not limited to this, and the central area can also be surrounded at the corner area.

[0080] For example, Fig. 9 for Figure 8 The enlarged structural diagram of the area D defined by the dashed line, combined with Figure 8 and Fig. 9 As shown, the through hole 101 further includes third through holes 101c arranged in an array in the transition region 104, the minimum distance between any two adjacent third through holes 101c is the fifth spacing d5, the minimum distance between any two adjacent first through holes 101a is the first spacing Da, and the minimum distance between any two adjacent second through holes 101b is the second spacing Db. Figure 8 and Fig. 9In the embodiment, the relative arrangement density of the first through holes 101a is less than the relative arrangement density of the second through holes 101b, the relative arrangement density of the third through holes 101c is less than the relative arrangement density of the second through holes 101b and greater than the relative arrangement density of the first through holes 101a, the first spacing Da is greater than the fifth spacing d5, and the fifth spacing d5 is greater than the second spacing Db.

[0081] For example, Fig. 9 As shown, the minimum distance between adjacent third through holes 101c and first through holes 101a is the sixth spacing d6, and the minimum distance between adjacent third through holes 101c and second through holes 101b is the seventh spacing d7. The sixth spacing d6 is greater than the fifth spacing d5 and less than the first spacing Da, and the seventh spacing d7 is less than the fifth spacing d5 and greater than the second spacing Db.

[0082] For example, in Fig. 9 In the figure, the first spacing Da, the second spacing Db, the fifth spacing d5 and the seventh spacing d7 are all spacings in the first direction X, and the sixth spacing d6 is a spacing in a direction on a plane formed by the first direction X and the second direction Y at a certain angle to the first direction X and the second direction Y, and the direction is determined according to the arrangement of the adjacent third through holes 101c and the first through holes 101a.

[0083] For example, in Figure 6 , Figure 7 , Figure 8 and Fig. 9 In the structure shown, the first through hole 101a, the second through hole 101b and the third through hole 101c have the same planar shape and the same planar size. Figure 6 , Figure 7 , Figure 8 and Fig. 9 The description is made by taking the shape of the through hole 101 as cylindrical and the plane shape as circular as an example. For through holes 101 of other shapes or sizes, the above-mentioned various spacings can be set according to the above-mentioned related descriptions, which will not be repeated here.

[0084] For example, Fig.10 A schematic diagram of a planar structure of another photonic crystal portion provided in at least one embodiment of the present disclosure is shown in FIG. Fig.10As shown, the first through holes 101a are arranged in a matrix, and the overall outer contour shape of the first through holes 101a arranged in the matrix is ​​a quadrilateral, and the second through holes 101b are arranged on one side of each side of the quadrilateral away from the center of the central area 102, and the second through holes 101b surround the entire first through holes 101a arranged in the matrix, so that the periphery of the matrix formed by the first through holes 101a is surrounded by the second through holes 101b, which can more fully suppress the energy in the two-dimensional photonic crystal microcavity from leaking from the peripheral area 103 or control the energy in the two-dimensional photonic crystal microcavity to radiate to the peripheral area 103.

[0085] For example, Fig.10 As shown, the array formed by the first through holes 101a is a square array, and the planar shape of the central area 102 is a square; the peripheral area 103 includes four side areas 103a and four corner areas 103b, and the shapes of the four side areas 103a and the four corner areas 103b are all rectangular; the long sides of each of the four side areas 103a close to the central area 102 are aligned with the four sides of the central area 102 and are of equal length; the four corner areas 103b are respectively located at the four corners of the central area 102 in the direction away from the center of the square, and the two adjacent sides of each of the four corner areas 103b are aligned with the short sides of the two adjacent side areas 103a close to it and are of equal length.

[0086] For example, Fig.10 As shown, the four side regions 103a are rectangular regions formed by Na×Nb second through holes 101b, and the four corner regions 103b are rectangular regions formed by Nb×Nb second through holes 101b, where Na and Nb are both positive integers, and Na is greater than Nb. Fig.10 In the figure, Na is 12, Nb is 4, the central area 102 includes 12*12 first through holes 101a, the side area 103a includes 12*4 second through holes 101b, and the corner area 103b includes 4*4 second through holes 101b. Of course, the embodiments of the present disclosure are not limited to this, and Na and Nb can also be other values, Na can also be less than Nb, or Na can be equal to Nb.

[0087] It should be noted that the size of the first through hole 101a in the central area 102, the first spacing Da and Na between two adjacent first through holes 101a can all be changed. The size and number of the second through holes 103b in the four side areas 103a and the four corner areas 103b, and the second spacing Db between adjacent second through holes 103b can all be adjusted. By adjusting the above features in the side areas 103a and the corner areas 103b, it is possible to suppress the energy in the microcavity included in the photonic crystal filter from leaking from the side areas 103a and the corner areas 103b or control the energy in the microcavity included in the photonic crystal filter to radiate to the side areas 103a and the corner areas 103b.

[0088] For example, in one example, by adjusting at least one of the second spacing Db between adjacent second through holes 103b in the side region 103a and the corner region 103b, the size of the second through holes 103b in the peripheral region, and the spacing between the side region 103a and the corner region 103b and the central region 102, the bandgap of the microcavity included in the photonic crystal filter can be formed, thereby confining the energy in the central region 102 and suppressing the leakage of the side energy of the microcavity.

[0089] For example, in one example, by separately adjusting the size of the second through holes 103b in the side region 103a and the corner region 103b corresponding to any direction of the side and / or the distance between adjacent second through holes 103b, the leakage of energy in the microcavity included in the photonic crystal filter can be controlled, so that the energy in the microcavity included in the photonic crystal filter can be radiated to any direction of the side.

[0090] For example, in one example, by separately adjusting the number of second through holes 103b in the side region 103a and the corner region 103b corresponding to any direction of the side, such as removing some of the second through holes 103b, the leakage of energy in the microcavity included in the photonic crystal filter in that direction can be controlled, so that the energy of the microcavity included in the photonic crystal filter can be radiated to any direction of the side.

[0091] For example, the structural design of the photonic crystal part 100 in the embodiment of the present disclosure can suppress the energy radiation from the top and bottom of the photonic crystal part 100 and the leakage of the side energy, and confine the energy in the microcavity included in the photonic crystal filter to improve the quality factor Q of the photonic crystal filter. At the same time, by destroying the partial energy suppression conditions of the microcavity included in the photonic crystal filter, the energy can be controlled to radiate in any direction, so as to achieve the energy coupling between the energy in the microcavity included in the photonic crystal filter and the energy of the optical structure outside the microcavity.

[0092] For example, Fig.11A schematic diagram of a planar structure of a plurality of photonic crystal portions arranged in an array and an enlarged structure of a single photonic crystal portion provided in at least one embodiment of the present disclosure, such as Fig.11 As shown, the minimum distance between two adjacent photonic crystal units is a fourth spacing Nag, and the fourth spacing Nag is greater than or equal to 5 microns and less than or equal to 10 microns. Fig.11 16 array-arranged photonic crystal sections are shown in FIG. 1 , but the embodiments of the present disclosure are not limited thereto, and more or fewer photonic crystal sections may be arranged in an array. Fig.11 The enlarged structural schematic diagram of a single photonic crystal portion also shows the first spacing Da, the second spacing Db, the third spacing Dg, as well as Na and Nb. Each photonic crystal portion satisfies the above-mentioned limiting condition of Na*Da+Nb*Db+Dg≤10μm, so that the accuracy of spectral detection can be improved when the photonic crystal filter is used in a spectral detection system.

[0093] For example, Fig.12 A schematic diagram of a cross-sectional structure of a photonic crystal filter provided in at least one embodiment of the present disclosure is shown in FIG. Fig.12 As shown, the photonic crystal filter 10 further includes an active layer 105 and a first dielectric layer 106 disposed between the active layer 105 and the photonic crystal portion 100. For example, the active layer 105 is configured to emit light and serve as an optical gain medium, and the material of the active layer 105 includes a fluorescent material.

[0094] For example, Fig.12 As shown, the photonic crystal filter 10 further includes a second dielectric layer 107 disposed on a side of the photonic crystal portion 100 away from the first dielectric layer 106, wherein each through hole 101 (including the first through hole 101a and the second through hole 101b) includes a first end and a second end opposite to each other along the extension direction of the channel thereof, the first end being connected to the first dielectric layer 106, and the second end being connected to the second dielectric layer 107. That is, the first dielectric layer 106 and the second dielectric layer 107 seal the through hole 101. The refractive index of the first dielectric layer 106 is n1, and the refractive index of the second dielectric layer 107 is n2. For example, the first dielectric layer 106 and the second dielectric layer 107 have the function of hole transmission or electron transmission.

[0095] For example, Fig.12 As shown, the through hole 101 is filled with a medium with a refractive index n0, which can be a gas (eg, air), a solid or a liquid material. In one example, the medium filled in the through hole 101 can also be the same medium as the material of the photonic crystal portion 100 .

[0096] For instance, in one example, the medium filled in the through hole 101 may be at least one of silicon, germanium, germanium silicon material, silicon compounds, germanium compounds, metals or III-V materials, and silicon compounds include at least one of silicon nitride, silicon dioxide, and silicon carbide. When the photonic crystal portion is double-layered or multi-layered, at least one layer is not penetrated.

[0097] The embodiments of the present disclosure do not limit the relationship between the refractive index n0 of the medium filled in the through hole 101, the refractive index n1 of the first medium layer 106, and the refractive index n2 of the second medium layer 107. In actual applications, the medium filled in the through hole 101, the first medium layer 106, and the second medium layer 107 can be set to have the same refractive index or different refractive indices as needed, and the embodiments of the present disclosure do not limit this.

[0098] For example, combined with Fig.12 The refractive index n0 of the medium filled in the through hole 101 is equal to 1, the refractive index n1 of the first medium layer 106 is equal to 1, the refractive index n2 of the second medium layer 107 is equal to 1, and the refractive index n2 of the photonic crystal portion 100 is equal to 3.48.

[0099] For example, in the embodiment of the present disclosure, the filling rate of the medium in the through hole 101 and the filling shape of the medium can also be adjusted as required. For example, in one example, the lower half of the through hole 101 can be filled or only one side of the through hole 101 can be filled, or the through hole 101 can be filled in any other filling manner. The materials of the first dielectric layer 106, the photonic crystal portion 100, and the second dielectric layer 107 and the material of the medium filled in the through hole 101 can be materials with optical gain or without optical gain.

[0100] For example, Fig.12 As shown, the photonic crystal filter 10 further includes: an n-type substrate 201, an n-type semiconductor heavily doped layer 202 and an n-type semiconductor doped layer 203 sequentially arranged on the n-type substrate 201, a p-type semiconductor doped layer 204 and a p-type semiconductor heavily doped layer 205 sequentially arranged on a side of the active layer 105 away from the n-type substrate 201, a p-type electrode layer 206 arranged on a side of the p-type semiconductor heavily doped layer 205 away from the n-type substrate 201; and an n-type electrode layer 207 arranged on a side of the n-type semiconductor heavily doped layer 202 away from the n-type substrate 201 and spaced from the n-type semiconductor doped layer 203, the active layer 105 is arranged on a side of the n-type semiconductor doped layer 203 away from the n-type substrate 201, the p-type semiconductor heavily doped layer 205 is configured as the second dielectric layer 107, and the p-type semiconductor doped layer 204 is configured as the photonic crystal portion 100 and the first dielectric layer 106.

[0101] For example, in Fig.12In the structure shown, the photonic crystal portion 100 and the first dielectric layer 106 are formed in the same process step and are integrally formed, and are both formed of a p-type semiconductor doping layer 204. It should be noted that if a first dielectric layer 106 is not retained under the photonic crystal portion 100 so that the p-type semiconductor doping layer 204 is not penetrated, the active layer 105 may be damaged during the formation of the photonic crystal portion 100, thereby weakening the luminescence and optical gain performance of the active layer 105.

[0102] For example, the material of the n-type substrate 201 includes but is not limited to GaAs, InP, GaSb or GaN, or the n-type substrate 201 can also be a substrate base formed by bonding a layer structure formed by GaAs, InP, GaSb or GaN on a Si substrate by a flip-chip bonding process.

[0103] For example, the structure of the active layer 105 includes: quantum wells, quantum wires or quantum dots; the material of the active layer 105 includes but is not limited to: GaAs, AlGaAs, InGaAs, InGaAsP, GaAsP, AlGaInAs, or InGaN, and the active layer 105 can be used to provide optical gain, and the gain spectrum peak wavelength range covers the ultraviolet to far infrared bands.

[0104] For example, the material of the n-type electrode layer 207 includes metals such as Au, AuGe, AuGe / Au, AuGeNiAu, or metal alloys, or transparent conductive materials such as indium tin oxide (ITO).

[0105] For example, the material of the p-type electrode layer 206 includes, but is not limited to, Au, Ti, Pt, Cr and other metals, and metal alloys such as TiPtAu, AuZnAu, NiAg or CrAu. For example, the p-type electrode layer 206 can be prepared by a stripping method, a wet etching method or a dry etching method. For example, when the dry etching method is used, the gas used is not limited to fluorocarbon gas, but is based on chlorine or hydroiodic acid gas. In addition, argon gas or xenon lamp inert gas needs to be mixed into chlorine or hydroiodic acid gas, and the ratio between chlorine or hydroiodic acid gas and inert gas is approximately 2:1.

[0106] For example, the p-type semiconductor heavily doped layer 205 is formed on the photonic crystal portion 100 by epitaxial growth or bonding.

[0107] For example, the materials of other layer structures of the photonic crystal filter 10 can be selected according to conventional materials, which is not limited in the embodiments of the present disclosure. The thickness of each layer structure of the photonic crystal filter 10 can be selected according to conventional designs as needed, which is not limited in the embodiments of the present disclosure.

[0108] It should be noted that the through hole 101 may also be formed in the p-type semiconductor heavily doped layer 205 to serve as the photonic crystal portion 100 .

[0109] For example, Fig.12 The working method of the photonic crystal filter 10 shown includes: when a positive voltage is applied to the P-type electrode layer 206, holes are injected from the p-type semiconductor heavily doped layer 205 to the active layer 105, and electrons are injected from the n-type semiconductor heavily doped layer 202 to the active layer 105. When holes and electrons (carriers) are injected into the active layer 105, the carriers recombine to emit light. The wavelength of the emitted light is defined by the energy band gap of the semiconductor layer included in the active layer 105.

[0110] For example, the p-type semiconductor heavily doped layer 205, the photonic crystal layer 204 to the n-type semiconductor heavily doped layer 202 form a multi-layer dielectric layer structure, and the light emitted in the active layer 105 excites the optical mode of the dielectric layer, and its evanescent light part reaches the photonic crystal part 100 and diffracts with the periodic structure of the photonic crystal part 100. When the wavelength of the optical mode has a limited matching relationship with the specified period of the photonic crystal in the photonic crystal part 100, the layered structure and the photonic crystal generate a stable resonant mode, which becomes a laser lasing mode.

[0111] For example, Fig.13 A schematic diagram of a cross-sectional structure of another photonic crystal filter provided in at least one embodiment of the present disclosure is shown in FIG. Fig.13 As shown, the photonic crystal filter 10 further includes: an n-type substrate 201, an n-type semiconductor heavily doped layer 202 and an n-type semiconductor doped layer 203 sequentially arranged on the n-type substrate 201, a p-type semiconductor doped layer 204 and a p-type semiconductor heavily doped layer 205 sequentially arranged on a side of the active layer 105 away from the n-type substrate 201, a p-type electrode layer 206 arranged on a side of the p-type semiconductor heavily doped layer 205 away from the n-type substrate 201, and an n-type electrode layer 207 arranged on a side of the n-type semiconductor heavily doped layer 202 away from the n-type substrate 201 and spaced from the n-type semiconductor doped layer 203; the active layer 105 is arranged on a side of the n-type semiconductor doped layer 203 away from the n-type substrate 201; the n-type semiconductor heavily doped layer 202 is configured as the second dielectric layer 107, and the n-type semiconductor doped layer 203 is configured as the photonic crystal portion 100 and the first dielectric layer 106.

[0112] For example, in Fig.13In the structure shown, a first dielectric layer 106 needs to be specially provided between the photonic crystal portion 100 and the active layer 105. The first dielectric layer 106 may also be formed of an n-type semiconductor doped material to prevent the material of the active layer 105 from filling the through hole 101 in the photonic crystal portion 100 during the process of forming the active layer 105 after forming the photonic crystal portion 100 having the through hole 101. In addition, if a first dielectric layer 106 is not specially provided between the n-type semiconductor doped layer 203 and the active layer 105, the epitaxial growth of the active layer 105 is also not conducive.

[0113] For example, Fig.13 The working method of the photonic crystal filter 10 shown includes: when a positive voltage is applied to the P-type electrode layer 206, holes are injected from the p-type semiconductor heavily doped layer 205 to the active layer 105, and electrons are injected from the n-type semiconductor heavily doped layer 202 to the active layer 105. When holes and electrons (carriers) are injected into the active layer 105, the carriers recombine to emit light. The wavelength of the emitted light is defined by the energy band gap of the semiconductor layer included in the active layer 105.

[0114] For example, the p-type semiconductor heavily doped layer 205, the photonic crystal layer 204 to the n-type semiconductor heavily doped layer 202 form a multi-layer dielectric layer structure, and the light emitted in the active layer 105 excites the optical mode of the dielectric layer, and its evanescent light part reaches the photonic crystal part 100 and diffracts with the periodic structure of the photonic crystal part 100. When the wavelength of the optical mode has a limited matching relationship with the specified period of the photonic crystal in the photonic crystal part 100, the layered structure and the photonic crystal generate a stable resonant mode, which becomes a laser lasing mode.

[0115] For example, Fig.13 The materials and thicknesses of the various layers of the photonic crystal filter 10 shown can be found in the above Fig.12 The relevant description in will not be repeated here.

[0116] For example, in an embodiment of the present disclosure, Fig.12 and Fig.13 The photonic crystal filter 10 shown includes a single-mode photonic crystal filter and a multi-mode photonic crystal filter.

[0117] At least one embodiment of the present disclosure also provides a method for preparing a photonic crystal filter, the preparation method comprising: providing a substrate; forming a first type of semiconductor doped layer film on the substrate; applying a resist on the first type of semiconductor doped layer film, and pre-curing it to form a resist layer; using an imprinting template to nano-imprint the resist layer to transfer the pattern of the imprinting template to the resist layer, and curing it to form a resist layer pattern; using the resist layer pattern as a mask to perform a composition process on the first type of semiconductor doped layer film to form a photonic crystal layer, and removing the resist layer pattern; the photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each photonic crystal unit includes a plurality of through holes arranged in an array, each photonic crystal unit includes a central area and a peripheral area surrounding the central area, and the plurality of through holes include a central area arranged in an array. The first through holes and the second through holes arranged in an array in the peripheral area; the central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between the first through hole and the second through hole is a third spacing Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied. The photonic crystal layer is prepared by nanoimprinting technology, which can reduce production costs and improve production efficiency, and is suitable for large-scale production, thereby reducing production costs and ensuring robustness. In addition, the quality factor of the photonic crystal layer prepared by conventional electron beam exposure method is not significantly improved compared with the photonic crystal layer prepared by nanoimprinting technology.

[0118] For example, Fig.14 A flow chart of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure, such as Fig.14 As shown, the preparation method includes the following steps.

[0119] S11: providing a substrate.

[0120] S12: forming a first type of semiconductor doping layer thin film on the substrate.

[0121] S13: applying a resist on the first type of semiconductor doping layer thin film, and performing a pre-curing treatment on the resist to form a resist layer.

[0122] S14: nano-imprinting the resist layer using an imprint template to transfer the pattern of the imprint template to the resist layer, and curing the resist layer to form a resist layer pattern.

[0123] S15: Using the resist layer pattern as a mask, a first type of semiconductor doped layer film is patterned to form a photonic crystal layer, and the resist layer pattern is removed, wherein the photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each photonic crystal unit includes a plurality of through holes arranged in an array, each photonic crystal unit includes a central area and a peripheral area surrounding the central area, the plurality of through holes include first through holes arranged in an array in the central area and second through holes arranged in an array in the peripheral area; the central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between a first through hole and a second through hole is a third spacing Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

[0124] For example, Figures 15A-15E A process diagram of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure.

[0125] like Fig.15A As shown, a substrate 301 is provided, which can be an n-type substrate. The material of the n-type substrate includes but is not limited to GaAs, InP, GaSb or GaN. Alternatively, the n-type substrate can also be a substrate formed by bonding a layer structure formed by GaAs, InP, GaSb or GaN on a Si substrate by a flip-chip bonding process.

[0126] For example, processing the base substrate 301 includes: cleaning and surface processing the base substrate 301 to ensure the flatness and cleanliness of the surface of the base substrate 301 .

[0127] For example, Fig. 15B As shown, a first type of semiconductor doping layer thin film 302 is formed on a substrate 301. For example, the first type of semiconductor doping layer thin film 302 may be an n-type semiconductor doping layer thin film or a p-type semiconductor doping layer thin film. For example, the first type of semiconductor doping layer thin film 302 may be formed by epitaxial growth.

[0128] For example, the first type of semiconductor doping layer film 302 can be applied on the substrate 301 by a spin coater or a coating machine, which can make the glue evenly coated on the surface of the substrate and control the thickness and uniformity of the first type of semiconductor doping layer film 302.

[0129] For example, Fig. 15CAs shown, a resist is applied on the first type of semiconductor doping layer film 302, and is pre-cured to form a resist layer 303. For example, a liquid resist may be applied on the first type of semiconductor doping layer film 302, and then the liquid resist may be pre-cured to make it in a non-free-flowing state, that is, a semi-solid state, and to ensure that the subsequent imprint template 304 can transfer its pattern to the resist layer 303. For example, the method of pre-curing the resist includes a method of using ultraviolet light irradiation or a method of temperature reduction curing.

[0130] For example, Fig.15D As shown, the resist layer 303 is nano-imprinted using an imprint template 304 to transfer the pattern of the imprint template 304 to the resist layer 303, and then the resist layer 303 is cured to form a resist layer pattern 305. Fig.15D The process of transferring the pattern of the imprint template 304 to the resist layer 303 is completed. For example, the portion of the resist layer pattern 305 covering the first type of semiconductor doping layer film is the portion retained by the first type of semiconductor doping layer film, and the uncovered portion is the etched portion. For example, the nanoimprint technology includes ultraviolet nanoimprint technology or thermal nanoimprint technology. For example, the method for curing the resist layer 303 includes a method of using ultraviolet light irradiation or a method of temperature reduction curing.

[0131] For example, in one example, the technology for nanoimprinting the resist layer 303 is ultraviolet nanoimprinting technology, and the method for curing the resist layer 303 is a method of using ultraviolet light irradiation; in another example, the technology for nanoimprinting the resist layer 303 is thermal nanoimprinting technology, and the method for curing the resist layer 303 is a temperature reduction curing method.

[0132] For example, Fig.15E As shown, the first type of semiconductor doping layer film 302 is patterned using the resist layer pattern 305 as a mask to form a photonic crystal layer, and the resist layer pattern 305 is removed. The planar structure of the photonic crystal portion 100 included in the photonic crystal layer can be seen in the above Figure 2-11 , I will not go into details here.

[0133] It should be noted that in Fig.15E In the embodiment, a portion of the first type semiconductor doped layer film 302 close to the substrate 301 is retained as the first dielectric layer. In other embodiments, the first type semiconductor doped layer film 302 may be etched through, and the portion of the first type semiconductor doped layer film 302 close to the substrate 301 is not retained.

[0134] For example, it should also be noted that the first type of semiconductor doped layer thin film may be a first type of semiconductor heavily doped layer thin film.

[0135] For example, the patterning process includes steps such as exposure, development, etching and degumming. Specifically, after the deposited film layer is subjected to proximity effect correction (PEC), the chip after photoresisting is placed in an electron beam exposure machine or a photolithography machine, and then the electron beam is scanned or applied through a mask to the surface of the photoresist layer to form the desired pattern. The exposed photoresist is then chemically treated so that the photoresist dissolves or solidifies in the developer to form the desired pattern. Etching and degumming include using chemical or physical methods to completely remove the unexposed photoresist layer from the surface of the substrate, while protecting the photoresist layer in the exposed area from being affected, exposing the underlying substrate or the photonic crystal structure at the bottom, and then using a suitable solvent or chemical solution to dissolve or remove the remaining photoresist to ensure the structural integrity and clarity of the photonic crystal layer.

[0136] For example, Fig.16 A flow chart of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure is shown in FIG. Fig.16 As shown, the preparation method includes the following steps.

[0137] S21: providing a substrate, and sequentially forming a second type of semiconductor heavily doped layer thin film, a second type of semiconductor doped layer thin film, an active layer thin film, and a first type of semiconductor doped layer thin film on the substrate.

[0138] S22: applying a resist on the first type of semiconductor doping layer thin film, and performing a pre-curing treatment on the resist to form a resist layer.

[0139] S23: nano-imprinting the resist layer using an imprint template to transfer the pattern of the imprint template to the resist layer, and curing the resist layer to form a resist layer pattern.

[0140] S24: Using the resist layer pattern as a mask, a first type of semiconductor doped layer film is patterned to form a photonic crystal layer and a first dielectric layer film, and the resist layer pattern is removed, wherein the first dielectric layer film is on a side of the photonic crystal layer close to the substrate, the photonic crystal layer includes a plurality of through holes arranged in an array, the photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each photonic crystal unit includes a plurality of through holes arranged in an array, each photonic crystal unit includes a central area and a peripheral area surrounding the central area, and the plurality of through holes are included in the central area. The first through holes are arranged in an array in the central area and the second through holes are arranged in an array in the peripheral area; the central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is the first spacing Da, the minimum distance between two adjacent second through holes is the second spacing Db, the minimum distance between the first through hole and the second through hole is the third spacing Dg, and satisfies Na*Da+Nb*Db+Dg≤10μm.

[0141] S25: forming a first type of semiconductor heavily doped layer thin film, a hard mask film and a photoresist layer in sequence on a side of the photonic crystal layer away from the substrate.

[0142] S26: patterning the photoresist layer to form a photoresist pattern covering a preset area, patterning the hard mask using the photoresist pattern as a mask, and removing the photoresist pattern to form a hard mask pattern.

[0143] S27: Using a hard mask pattern as a mask, a first type of semiconductor heavily doped layer film, a photonic crystal layer, a first dielectric layer film, an active layer film, and a second type of semiconductor doped layer film are patterned to form a second dielectric layer, a photonic crystal portion, a first dielectric layer, an active layer, and a second type of semiconductor doped layer, respectively, and there is a gap between the edge of the orthographic projection of the second type of semiconductor doped layer on the substrate and the edge of the orthographic projection of the second type of semiconductor heavily doped layer film on the substrate.

[0144] S28: removing the hard mask pattern, forming a p-type electrode layer on a side of the second dielectric layer away from the substrate, and forming an n-type electrode layer on a side of the second type of semiconductor heavily doped layer film away from the substrate in the gap.

[0145] For example, Figures 17A-17H A process diagram of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure.

[0146] For example, Fig.17AAs shown, a substrate 301 is provided, and a second type of semiconductor heavily doped layer film 306 , a second type of semiconductor doped layer film 307 , an active layer film 308 and a first type of semiconductor doped layer film 302 are sequentially formed on the substrate 301 .

[0147] For example, the first type of semiconductor doped layer film 302 is a p-type semiconductor doped layer film, the second type of semiconductor doped layer film 307 is an n-type semiconductor doped layer film, and the second type of semiconductor heavily doped layer film 306 is an n-type semiconductor heavily doped layer film. The n-type semiconductor heavily doped layer film 306, the n-type semiconductor doped layer film 307, the active layer film 308 and the p-type semiconductor doped layer film 302 are sequentially stacked on the substrate 301. For example, the p-type semiconductor doped layer film can be formed by epitaxial growth.

[0148] For example, the active layer formed by the active layer thin film 308 can emit light and can be used as an optical gain medium. The material of the active layer thin film 308 can refer to the relevant design mentioned above, which will not be described in detail here.

[0149] For example, Fig. 17B As shown, a resist is applied on the first type of semiconductor doping layer film 302, and pre-cured to form a resist layer 303, that is, a resist is applied on the n-type semiconductor doping layer film 302, and pre-cured to form a resist layer 303. For example, a liquid resist may be applied on the n-type semiconductor doping layer film 302, and then the liquid resist may be pre-cured to make it in a non-free-flowing state, that is, a semi-solid state, and it can be ensured that the subsequently mentioned imprint template 304 can transfer its pattern to the resist layer 303. For example, the method of pre-curing the resist includes a method of using ultraviolet light irradiation or a method of temperature reduction curing.

[0150] For example, Fig. 17C As shown, the resist layer 303 is nano-imprinted using an imprint template 304 to transfer the pattern of the imprint template 304 to the resist layer 303 , which is then cured to form a resist layer pattern 305 .

[0151] For example, the nanoimprint technology includes ultraviolet nanoimprint technology or thermal nanoimprint technology.

[0152] For example, the method of curing the resist layer 303 includes a method of using ultraviolet light irradiation or a method of curing by cooling.

[0153] For example, in one example, the technology for nanoimprinting the resist layer 303 is ultraviolet nanoimprinting technology, and the method for curing the resist layer 303 is a method of using ultraviolet light irradiation; in another example, the technology for nanoimprinting the resist layer 303 is thermal nanoimprinting technology, and the method for curing the resist layer 303 is a temperature reduction curing method.

[0154] For example, Fig.17D As shown, the first type of semiconductor doping layer film 302 (p-type semiconductor doping layer film) is patterned using the resist layer pattern 305 as a mask to form a photonic crystal layer and a first dielectric layer film 309, and the resist layer pattern 305 is removed. The first dielectric layer film 309 is on the side of the photonic crystal layer close to the substrate 301. The planar structure of the photonic crystal portion 100 included in the photonic crystal layer can be seen in the above Figure 2-11 As shown, no further description is given here.

[0155] For example, the photonic crystal portion manufactured using the nanoimprint technology includes holes of various shapes, hole arrays, nano-grooves of various shapes, and combinations of various nano-structures thereof, which are not limited in the embodiments of the present disclosure.

[0156] For example, in the process of patterning the p-type semiconductor doped layer film using the resist layer pattern 305 as a mask to form a photonic crystal layer, a first dielectric layer film 309 is simultaneously formed on the side of the photonic crystal layer close to the base substrate 301, and the photonic crystal layer and the first dielectric layer film 309 are an integrated structure. The first dielectric layer film 309 has a certain thickness and is also retained in the area corresponding to the through hole 101, that is, the first dielectric layer film 309 is a continuous layer structure.

[0157] For example, Fig.17D As shown, the first dielectric layer film 309 is formed between the active layer film 308 and the photonic crystal portion 100 . The presence of the first dielectric layer film 309 can prevent the first type of semiconductor doped layer film 302 from being etched through, thereby preventing the performance of the active layer film 308 from being affected.

[0158] For example, the portion of the first type of semiconductor doping layer film 302 covered by the resist layer pattern 305 is the reserved portion of the first type of semiconductor doping layer film, and the uncovered portion is the etched portion.

[0159] For example, Fig.17DAs shown, the second type of semiconductor doped layer film 307 and the active layer film 308 are arranged on the same surface of the substrate 301 and are stacked with the photonic crystal portion 100, and the active layer film 308 is sandwiched between the photonic crystal portion 100 and the second type of semiconductor doped layer film 306, and the second type of semiconductor heavily doped layer film 306 is formed on the side of the second type of semiconductor doped layer film 307 away from the active layer film 308.

[0160] For example, Fig.17E As shown, a first type of semiconductor heavily doped layer film 310 (p-type semiconductor heavily doped layer film), a hard mask 311 and a photoresist layer 312 are sequentially formed on a side of the photonic crystal layer away from the substrate 301 .

[0161] For example, the first type of semiconductor heavily doped layer film 310 can be formed on the surface of the photonic crystal layer by epitaxial growth. The material of the hard mask 311 includes silicon dioxide, and the hard mask 311 can be formed by epitaxial growth or coating, and then a photoresist layer 312 is coated on the hard mask 311.

[0162] For example, Fig.17F As shown, the photoresist layer 312 is patterned to form a photoresist pattern 313 covering a predetermined area, and the hard mask 311 is patterned using the photoresist pattern 313 as a mask and the photoresist pattern 313 is removed to form a hard mask pattern 314 .

[0163] For example, the preset area is the mesa area of ​​the photonic crystal filter, and the mesa area of ​​the photonic crystal filter can be defined by electron beam exposure and development, and then the portion of the hard mask 311 other than the mesa area is etched away to form a hard mask pattern 314 .

[0164] For example, Figure 17GAs shown, the first type of semiconductor heavily doped layer thin film 310 (second dielectric layer thin film), photonic crystal layer, first dielectric layer thin film 309, active layer thin film 308 and second type of semiconductor doped layer thin film 307 (n-type semiconductor doped layer thin film) are patterned using the hard mask pattern 314 as a mask to form the second dielectric layer 107, photonic crystal portion 100, first dielectric layer 106, active layer 105 and second type of semiconductor doped layer 203 (n-type semiconductor doped layer 203), respectively, and there is a gap between the edge of the orthographic projection of the second type of semiconductor doped layer 203 (n-type semiconductor doped layer 203) on the substrate 301 and the edge of the orthographic projection of the second type of semiconductor heavily doped layer thin film 306 (n-type semiconductor heavily doped layer thin film) on the substrate 301. That is, the mesa of the photonic crystal filter is etched using the hard mask pattern 314 as a mask until the second type of semiconductor heavily doped layer thin film 306 is exposed, and then the hard mask pattern 314 is removed.

[0165] For example, Figure 17G As shown, the first type of semiconductor heavily doped layer film 310 can be used as a second dielectric layer film, and the second dielectric layer film can be formed into a second dielectric layer 107 through a subsequent etching process. Fig.12 Each through hole 101 includes a first end 1011 and a second end 1012 opposite to each other along the extension direction of the channel thereof. The first end 1011 is connected to the first dielectric layer 106 , and the second end 1012 is connected to the second dielectric layer 107 .

[0166] For example, Fig.17H As shown, the hard mask pattern 314 is removed, a p-type electrode layer 316 is formed on the side of the second dielectric layer 107 away from the substrate 301 , and an n-type electrode layer 317 is formed in the gap on the side of the second type of semiconductor heavily doped layer film 306 away from the substrate 301 .

[0167] For example, the p-type electrode layer 316 can be formed by depositing a p-type electrode material, and the n-type electrode layer 317 can be formed by depositing an n-type electrode material. The embodiments of the present disclosure are not limited to this, as long as the p-type electrode layer 316 and the n-type electrode layer 317 can be prepared.

[0168] For example, by Figures 17A-17H The structure of the photonic crystal filter can be seen in the above Fig.12 The relevant description in will not be repeated here.

[0169] It should be noted that the photonic crystal portion can also be formed in the first type of semiconductor heavily doped layer film 310. In this case, the formation steps of the first type of semiconductor heavily doped layer film 310 and the first type of semiconductor doped layer film 302 need to be exchanged, and the other process steps remain unchanged.

[0170] For example, Fig.18 A flow chart of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure is shown in FIG. Fig.18 As shown, the preparation method includes the following steps.

[0171] S31: providing a substrate, and sequentially forming a first type of semiconductor heavily doped layer thin film and a first type of semiconductor doped layer thin film on the substrate.

[0172] S32: applying a resist on the first type of semiconductor doping layer thin film, and performing a pre-curing treatment on the resist to form a resist layer.

[0173] S33: nano-imprinting the resist layer using an imprint template to transfer the pattern of the imprint template to the resist layer, and curing the resist layer to form a resist layer pattern.

[0174] S34: Using the resist layer pattern as a mask, a first type of semiconductor doped layer film is patterned to form a photonic crystal layer, and the resist layer pattern is removed, the photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each photonic crystal unit includes a plurality of through holes arranged in an array, each photonic crystal unit includes a central area and a peripheral area surrounding the central area, the plurality of through holes include first through holes arranged in an array in the central area and second through holes arranged in an array in the peripheral area; the central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between a first through hole and a second through hole is a third spacing Dg, and satisfies Na*Da+Nb*Db+Dg≤10μm.

[0175] S35: epitaxially growing a first dielectric layer thin film on the photonic crystal layer.

[0176] S36: forming a second type of semiconductor doped layer film, a second type of semiconductor heavily doped layer film, a hard mask and a photoresist layer in sequence on a side of the first dielectric layer film away from the substrate.

[0177] S37: patterning the photoresist layer to form a photoresist pattern covering a preset area, patterning the hard mask using the photoresist pattern as a mask, and removing the photoresist pattern to form a hard mask pattern.

[0178] S38: Using the hard mask pattern as a mask, a second type of semiconductor heavily doped layer thin film, a second type of semiconductor doped layer thin film, an active layer thin film, a first dielectric layer thin film and a photonic crystal layer are subjected to a composition process to form a second type of semiconductor heavily doped layer, a second type of semiconductor doped layer, an active layer, a first dielectric layer and a photonic crystal portion, respectively, and there are gaps between the edge of the orthographic projection of the photonic crystal portion on the substrate and the edge of the orthographic projection of the first type of semiconductor heavily doped layer thin film on the substrate.

[0179] S39: remove the hard mask pattern, form a p-type electrode layer on the side of the second type of semiconductor heavily doped layer away from the substrate, and form an n-type electrode layer in the gap on the side of the first type of semiconductor heavily doped layer film away from the substrate.

[0180] For example, Figures 19A-19I A process diagram of a method for preparing a photonic crystal filter provided in at least one embodiment of the present disclosure.

[0181] For example, Fig.19A As shown, a substrate 301 is provided, and a first type of semiconductor heavily doped layer thin film 310 and a first type of semiconductor doped layer thin film 302 are sequentially formed on the substrate 301 .

[0182] For example, the first type of semiconductor doped layer film 302 is an n-type semiconductor doped layer film, and the first type of semiconductor heavily doped layer film 310 is an n-type semiconductor heavily doped layer film. The n-type semiconductor heavily doped layer film and the n-type semiconductor doped layer film are sequentially stacked on the substrate 301. For example, the n-type semiconductor heavily doped layer film and the n-type semiconductor doped layer film can be formed by epitaxial growth. The second type of semiconductor doped layer film mentioned later is a p-type semiconductor doped layer.

[0183] For example, Fig.19BAs shown, a resist is applied on the first type of semiconductor doping layer film 302, and pre-cured to form a resist layer 303, that is, a resist is applied on the n-type semiconductor doping layer film 302, and pre-cured to form a resist layer 303. For example, a liquid resist may be applied on the n-type semiconductor doping layer film 302, and then the liquid resist may be pre-cured to make it in a non-free-flowing state, that is, a semi-solid state, and it can be ensured that the imprint template 304 can transfer its pattern to the resist layer 303. For example, the method of pre-curing the resist includes a method of using ultraviolet light irradiation or a method of temperature reduction curing.

[0184] For example, Fig.19C As shown, the resist layer 303 is nano-imprinted using an imprint template 304 to transfer the pattern of the imprint template 304 to the resist layer 303 , which is then cured to form a resist layer pattern 305 .

[0185] For example, the nanoimprint technology includes ultraviolet nanoimprint technology or thermal nanoimprint technology.

[0186] For example, the method of curing the resist layer 303 includes a method of using ultraviolet light irradiation or a method of curing by cooling.

[0187] For example, in one example, the technology for nanoimprinting the resist layer 303 is ultraviolet nanoimprinting technology, and the method for curing the resist layer 303 is a method using ultraviolet light irradiation; in another example, the technology for imprinting the resist layer 303 is thermal nanoimprinting technology, and the method for curing the resist layer 303 is a temperature reduction curing method.

[0188] For example, Fig.19DAs shown, the first type of semiconductor doping layer film 302 (n-type semiconductor doping layer film) is patterned using the resist layer pattern 305 as a mask to form a photonic crystal layer, and the resist layer pattern 305 is removed. The photonic crystal layer includes a plurality of through holes arranged in an array, the photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each photonic crystal unit includes a plurality of through holes arranged in an array, each photonic crystal unit includes a central area and a peripheral area surrounding the central area, the plurality of through holes include first through holes arranged in an array in the central area and second through holes arranged in an array in the peripheral area; the central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; the number of the second through holes on each side of the peripheral area is Na×Nb, wherein Nb is a positive integer greater than or equal to 1; the minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between a first through hole and a second through hole is a third spacing Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

[0189] For example, the portion of the first type of semiconductor doping layer film 302 covered by the resist layer pattern 305 is the reserved portion of the first type of semiconductor doping layer film, and the uncovered portion is the etched portion.

[0190] For example, the photonic crystal portion manufactured using the nanoimprint technology includes holes of various shapes, hole arrays, nano-grooves of various shapes, and combinations of various nano-structures thereof, which are not limited in the embodiments of the present disclosure.

[0191] For example, Fig.19E As shown, a first dielectric layer thin film 309 is formed by epitaxial growth on the photonic crystal layer.

[0192] For example, the first dielectric layer film 309 is on a side of the photonic crystal layer away from the base substrate 301 .

[0193] For example, Fig.19F As shown, an active layer film 308 , a second type of semiconductor doped layer film 307 , a second type of semiconductor heavily doped layer film 306 , a hard mask 311 and a photoresist layer 312 are sequentially formed on the side of the first dielectric layer film 309 away from the substrate 301 .

[0194] For example, the second type of semiconductor doped layer film 307 can be formed on the surface of the first dielectric layer film 309 by epitaxial growth. The material of the hard mask 311 includes silicon dioxide, and the hard mask 311 can be formed by epitaxial growth or coating, and then a photoresist layer 312 is coated on the hard mask 311.

[0195] For example, Figure 19G As shown, the photoresist layer 312 is patterned to form a photoresist pattern 313 covering a predetermined area, and the hard mask 311 is patterned using the photoresist pattern 313 as a mask and the photoresist pattern 313 is removed to form a hard mask pattern 314 .

[0196] For example, the preset area is the mesa area of ​​the photonic crystal filter, and the mesa area of ​​the photonic crystal filter can be defined by electron beam exposure and development, and then the portion of the hard mask 311 other than the mesa area is etched away to form a hard mask pattern 314 .

[0197] For example, Fig.19H As shown, the second type of semiconductor heavily doped layer thin film 306, the second type of semiconductor doped layer thin film 307, the active layer thin film 308, the first dielectric layer thin film 309 and the photonic crystal layer are patterned using the hard mask pattern 314 as a mask to form the second type of semiconductor heavily doped layer (p-type semiconductor heavily doped layer 205), the second type of semiconductor doped layer (p-type semiconductor doped layer 204), the active layer 105, the first dielectric layer 106 and the photonic crystal portion 100, respectively, and there is a gap between the edge of the orthographic projection of the photonic crystal portion 100 on the substrate 301 and the edge of the orthographic projection of the first type of semiconductor heavily doped layer thin film 310 (n-type semiconductor heavily doped layer thin film) on the substrate 301. That is, the mesa of the photonic crystal filter is etched using the hard mask pattern 314 as a mask until the first type of semiconductor heavily doped layer thin film 310 is exposed, and then the hard mask pattern 314 is removed.

[0198] For example, Fig.19H As shown, the active layer 105 can emit light and can be used as an optical gain medium. The material of the active layer thin film 105 can refer to the relevant design mentioned above and will not be described again here.

[0199] For example, Fig.19H As shown, the first type of semiconductor heavily doped layer film 310 can be used as the second dielectric layer film, and the second dielectric layer film is the second dielectric layer. Fig.13 Each through hole 101 includes a first end 1011 and a second end 1012 along the extension direction of the channel. The first end 1011 is connected to the first dielectric layer film 309 (the first dielectric layer is formed later), and the second end 1012 is connected to the second dielectric layer film 310 (the first dielectric layer is formed later).

[0200] For example, Fig.19IAs shown, the hard mask pattern 314 is removed, a p-type electrode layer 316 is formed on the side of the second type of semiconductor heavily doped layer 205 away from the substrate 301, and an n-type electrode layer 317 is formed in the gap on the side of the first type of semiconductor heavily doped layer film 310 away from the substrate 301.

[0201] For example, the p-type electrode layer 316 can be formed by depositing a p-type electrode material, and the n-type electrode layer 317 can be formed by depositing an n-type electrode material. The embodiments of the present disclosure are not limited to this, as long as the p-type electrode layer 316 and the n-type electrode layer 317 can be prepared.

[0202] For example, by Figures 19A-19I The structure of the photonic crystal filter can be seen in the above Fig.13 The relevant description in will not be repeated here.

[0203] It should be noted that the photonic crystal portion can also be formed in the first type of semiconductor heavily doped layer film 310. In this case, the formation steps of the first type of semiconductor heavily doped layer film 310 and the first type of semiconductor doped layer film 302 need to be exchanged, and the other process steps remain unchanged.

[0204] For example, Fig. 20 A block diagram of a spectrum detection system provided by at least one embodiment of the present disclosure, such as Fig. 20 As shown, the spectrum detection system 400 includes: a semi-transmitting and semi-reflecting mirror 401, an objective lens 402, an imaging structure 403, a 4f optical system 404 and the photonic crystal filter 10 in any of the above embodiments.

[0205] For example, the pattern of the structure to be detected can be detected through the optical path based on the 4f optical system 404, so that the rich pattern generated in the volume of the extremely small array unit represents the high Q resonance peaks corresponding to different characteristic wavelengths generated by the structure to be detected. The method of using the spectrum detection system for spectrum detection can be through out-of-plane excitation, so there is no need for coupling and modulation, and the structure of the spectrum detection system is simple, and higher spectrum detection accuracy can be achieved through simple photonic crystal partial arraying, and the spectrum detection accuracy is adjustable. In addition, the size of the spectrum detection system is smaller, which is conducive to further realizing a miniaturized spectrum detector.

[0206] For example, a 4f optical system means that when two coherent polarized lights are input, they pass through special optical devices, such as cosine gratings and exchange planes, so that the input lights produce diffraction spectra on the screen. The precise transverse movement of the cosine grating can continuously change the phase difference of the diffraction order of the two beams of light to achieve the purpose of subtracting or adding the diffracted light intensity, that is, there are two lenses with a focal length of f, 2f apart, an object distance of f, and a phase distance of f, so it is a 4f optical system, and only an optical system with a distance greater than 4f can be used as a zoom system.

[0207] For example, combined with Fig.11 The planar structure of the photonic crystal filter in the 600nm SOI process platform and the measurement system integrating the 4f optical system and polarization filtering method, the SOI pattern is firstly subjected to write field correction (PEC) by the Beamer software, the write field size is selected as 500 microns * 500 microns, the sub-write field size is selected as 10 microns * 10 microns, and the write field correction is realized by the Beamer software. The processing and manufacturing are realized by electron beam exposure (EBL) and inductively coupled plasma etching (ICP), and the size of the formed photonic crystal microcavity pattern is about 10 microns × 10 microns.

[0208] For example, the host computer controls the multi-spectrum light source, and presents a pattern of appropriate size on the imaging structure 403 through the 4f optical system. At the same time, the host computer synchronously captures the presented pattern and PD response for recording, wherein the magnification of the 4f optical system 404 is 0.5.

[0209] The embodiments of the present disclosure solve the problem of a spectral detection system and a spectral detection method based on a photonic crystal filter. The photonic crystal part included in the spectral detection system has regularly shaped units, each of which has a variety of frequency selection capabilities at different wavelengths. The frequency selection capabilities can be adjusted according to the required spectral recovery accuracy, and the wavelengths corresponding to the characteristic frequencies of adjacent units in the array unit are uncorrelated, thereby effectively avoiding coupling between adjacent units in the array unit due to similar wavelengths.

[0210] For example, the spectrum detection method includes forming spectrums to be measured with different characteristics, inputting the spectrums to be measured into any of the spectrum detection systems described above to distinguish the spectrums to be measured with different characteristics, and the spectrum detection method includes the following steps.

[0211] First, a light source is irradiated, and a spectrum to be measured with different characteristics is formed by a host computer. After using a polarization filtering method, a part of the light passes through a semi-transmitting and semi-reflecting mirror, and is irradiated onto a photonic crystal filter through an objective lens. The reflected light from the photonic crystal filter passes through the objective lens again to the semi-transmitting and semi-reflecting mirror, so that this part of the light enters the 4f optical system. The 4f optical system is designed to have a magnification that matches the field of view and the imaging structure, and presents a near-field pattern generated by the light passing through the photonic crystal filter on the imaging structure.

[0212] Second, the host computer controls the waveform shaper to modulate the wide-spectrum light source. At the same time, the patterns of the imaging structure obtained by measuring the test optical path under different spectra are recorded. Combined with the filtering characteristics of the photonic crystal filter, the recorded data is processed and analyzed in conjunction with the neural network to obtain the spectral information of the light source to be tested.

[0213] Third, by recording a large number of input unknown spectra and the corresponding near-field patterns of the test as the input of the neural network for training, the pre-trained EfficientNet-B0 model was used, and a custom loss function of cosine similarity loss and mean square error loss was combined. A specific learning rate adjustment mechanism and regularization were combined to prevent overfitting in training to improve the training effect of the model. The whole process includes data preparation, model training, verification and testing, and the loss curve during training is visualized.

[0214] For example, the photonic crystal filter provided by the embodiments of the present disclosure can be applied to a spectral detection system to obtain the following technical effects: the photonic crystal filter produces a wealth of high-Q resonances and corresponding rich near-field pattern features, has excellent frequency selection characteristics in an extremely small volume, and can be adapted to more application scenarios through out-of-plane coupling. In addition, spectral detection can be achieved without calibration through the training of a neural network, and has good robustness to process errors in processing, thereby facilitating large-scale industrial production.

[0215] For example, Fig.21 The pattern of the photonic crystal microcavity array measured by the spectrum test system with a photonic crystal filter provided by at least one embodiment of the present disclosure is Fig.21During the spectral test shown, the input wavelength was 1550nm and the line width was 10pm. After considering the inherent CMOS noise and environmental background noise, 2% Gaussian noise was added to 40% of the acquired images. These processed images were used as the input of the neural network. The spectral reconstruction network is based on the EfficientNet-B0 architecture and the input is a grayscale image with a resolution of 1280×1024×1. The image is sampled through the initial 3×3 convolution layer to extract the initial features. The subsequent network uses the MBConv module to optimize the computational efficiency, gradually adjust the number of channels and reduce the spatial resolution, and finally generate a 1280-dimensional vector through global average pooling. The fully connected layer outputs 1600 nodes, supporting the spectral reconstruction task with a wavelength range of 80 nanometers and an accuracy of 0.05 nanometers. The neural network uses the Swish activation function and applies batch normalization and dropout (dropout rate of 30%) after each convolutional neural network and fully connected layer for regularization to prevent overfitting. During training, the AdamW optimizer was used with an initial learning rate of 0.0001, and learning rate decay was applied when performance on the validation set plateaued. The loss function was a combination of MSE and cosine similarity, evaluated between the network output and a standard spectrum. The model was trained in 90 epochs, performance was monitored using the validation set, and a final evaluation was performed on the test set, with model weights and predictions saved. The entire process includes data preparation, model training, validation, and testing, and the loss curve during training is visualized.

[0216] For example, Fig. 22 A loss curve diagram of a demodulation spectrum neural network training process provided by at least one embodiment of the present disclosure, from Fig. 22 It can be seen that the loss value obtained by training is 10 -3 The goodness of fit of the order of magnitude spectrum is greater than 97%. The difference comes from the non-ideality caused by process errors, sensitivity of the imaging structure, noise, etc.

[0217] For example, Fig.23 A demodulation spectrum performance characterization diagram provided for at least one embodiment of the present disclosure, such as Fig.23 As shown, when the input spectrum is a multi-peak spectrum, the spectrum detection system and test results provided by the embodiments of the present disclosure demonstrate a spectrum demodulation capability, which exhibits a resolution of 0.25nm at a bandwidth of 80nm in the reconstruction of multi-feature spectra with different characteristics, such as high and low amplitudes, and multiple resonance peaks with different line widths.

[0218] The spectrum test system of the two-dimensional photonic crystal microcavity array designed by the above method can be applied to the fields of microcavity array sensors, microcavity detectors, etc.

[0219] For example, in a microcavity sensor, the photonic crystal filter provided by the embodiments of the present disclosure has the characteristics of strong frequency selection capability and wide detection range, that is, as a microcavity sensor, it has the characteristics of high wavelength resolution. Therefore, the influence of environmental factors such as temperature and humidity on the microcavity sensor can be measured by measuring the changes in the pattern of the two-dimensional photonic crystal microcavity array to prepare a sensor with high sensitivity.

[0220] For example, in a spectral imager, the photonic crystal filter provided by the embodiments of the present disclosure has the characteristics of miniaturization and wide spectral detection range, that is, it can be used as a spectral imager with imaging and high wavelength resolution characteristics by dense paving. Therefore, a spectral imager with spatial data can be prepared by measuring the imaging algorithm of multiple array pattern sets after dense paving.

[0221] For example, Fig.24 The simulation performance diagram of the spectral detection system for avoiding the write field splicing problem provided by at least one embodiment of the present disclosure is as follows: Fig.24 As shown in the figure, the performance graphs of the simulations for structural units larger than and smaller than 10 microns * 10 microns (Na=7, Nb=8) are compared when there are problems such as writing field splicing, mechanical movement, field distortion, and edge effects in electron beam exposure. When there is an 80nm offset in the x-direction or y-direction beyond the 10 micron * 10 micron writing field range, the microcavity Q value will change from 22×10 4 Down to 8×10 4 , while the structure (Na=6, Nb=7) proposed in the embodiment of the present disclosure does not have such an effect when the write field offset occurs, and can maintain the Q value at 16×10 4 The array unit that can be smaller than 10 microns*10 microns proposed in the embodiments of the present disclosure can effectively avoid the above problems, so that the spectrum detection system has high robustness.

[0222] The spectral detection system and spectral detection method provided by the embodiments of the present disclosure can detect the pattern of the structure to be detected through an optical path based on the 4f optical system. In addition, rich patterns can be generated in an extremely small array unit volume, which represents the corresponding high-Q resonance peaks of different characteristic wavelengths generated by the structure to be detected, thereby realizing the detection of the spectrum to be detected.

[0223] There are a few points to note:

[0224] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to the general design.

[0225] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is enlarged or reduced, that is, these drawings are not drawn according to the actual scale.

[0226] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0227] The above description is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. The protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A photonic crystal filter, comprising: Photonic crystal section, where The photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each of the photonic crystal units includes a plurality of through holes arranged in an array, Each of the photonic crystal units comprises a central region and a peripheral region surrounding the central region, and the plurality of through holes comprises first through holes arranged in an array in the central region and second through holes arranged in an array in the peripheral region; The central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; The number of the second through holes on each side of the peripheral area is Na×Nb, where Nb is a positive integer greater than or equal to 1; The minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between the first through hole and the second through hole is a third spacing Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

2. The photonic crystal filter according to claim 1, wherein: The minimum distance between two adjacent photonic crystal units is a fourth spacing Nag, and the fourth spacing Nag is greater than or equal to 5 micrometers and less than or equal to 10 micrometers.

3. The photonic crystal filter according to claim 1 or 2, wherein: There is also a transition area between the central area and the peripheral area, and the through holes also include third through holes arranged in an array in the transition area, the minimum distance between any two adjacent third through holes is the fifth spacing, the arrangement density of the first through holes is greater than the arrangement density of the third through holes, and the arrangement density of the third through holes is greater than the arrangement density of the second through holes, the first spacing is less than the fifth spacing, and the fifth spacing is less than the second spacing; or the arrangement density of the first through holes is less than the arrangement density of the third through holes, and the arrangement density of the third through holes is less than the arrangement density of the second through holes, the first spacing is greater than the fifth spacing, and the fifth spacing is greater than the second spacing.

4. The photonic crystal filter according to claim 3, wherein: The first through hole, the second through hole and the third through hole have the same planar shape, the planar size of the first through hole is smaller than the planar size of the second through hole, and the planar size of the second through hole is smaller than the planar size of the third through hole.

5. The photonic crystal filter according to any one of claims 1 to 4, wherein: The first through holes are arranged in a matrix, and the overall outer contour of the first through holes arranged in the matrix is ​​a quadrilateral. The second through holes are arranged on one side of each side of the quadrilateral away from the center of the central area, and the second through holes surround the entire first through holes arranged in the matrix.

6. The photonic crystal filter according to claim 5, wherein: The rectangular array formed by the first through holes is a square array, and the planar shape of the central area is a square; The peripheral area includes four side areas and four corner areas, and the shapes of the four side areas and the four corner areas are all rectangular; The long sides of each of the four side regions close to the central region are respectively aligned with the four sides of the central region and have the same length; The four corner regions are respectively located at the four corners of the central region in a direction away from the center of the square, and two adjacent sides of each of the four corner regions are respectively aligned with the short sides of the two adjacent side regions and have the same length.

7. The photonic crystal filter according to claim 6, wherein: The four side regions are all rectangular regions formed by Na×Nb second through holes, and the four corner regions are all square regions formed by Nb×Nb second through holes, and Na and Nb are both positive integers.

8. The photonic crystal filter according to any one of claims 1 to 7, further comprising an active layer and a first dielectric layer disposed between the active layer and the photonic crystal portion, wherein: The active layer is configured to emit light and serve as an optical gain medium.

9. The photonic crystal filter according to claim 8, further comprising a second dielectric layer disposed on a side of the photonic crystal portion away from the first dielectric layer, wherein: Each of the through holes includes a first end and a second end opposite to each other along the extension direction of the through hole, wherein the first end is connected to the first dielectric layer, and the second end is connected to the second dielectric layer.

10. The photonic crystal filter according to claim 9, further comprising: n-type substrate; An n-type semiconductor heavily doped layer and an n-type semiconductor doped layer are sequentially disposed on the n-type substrate; A p-type semiconductor doped layer and a p-type semiconductor heavily doped layer are sequentially arranged on a side of the active layer away from the n-type substrate; A p-type electrode layer disposed on a side of the p-type semiconductor heavily doped layer away from the n-type substrate; as well as An n-type electrode layer is disposed on a side of the n-type semiconductor heavily doped layer away from the n-type substrate and spaced apart from the n-type semiconductor doped layer; Wherein, the active layer is arranged on a side of the n-type semiconductor doping layer away from the n-type substrate; The p-type semiconductor heavily doped layer is configured as the second dielectric layer; The p-type semiconductor doping layer is configured as the photonic crystal portion and the first dielectric layer.

11. The photonic crystal filter according to claim 9, further comprising: n-type substrate; An n-type semiconductor heavily doped layer and an n-type semiconductor doped layer are sequentially disposed on the n-type substrate; A p-type semiconductor doped layer and a p-type semiconductor heavily doped layer are sequentially arranged on a side of the active layer away from the n-type substrate; a p-type electrode layer disposed on a side of the p-type semiconductor heavily doped layer away from the n-type substrate, and An n-type electrode layer is disposed on a side of the n-type semiconductor heavily doped layer away from the n-type substrate and spaced apart from the n-type semiconductor doped layer; Wherein, the active layer is arranged on a side of the n-type semiconductor doping layer away from the n-type substrate; The n-type semiconductor heavily doped layer is configured as the second dielectric layer; The n-type semiconductor doping layer is configured as the photonic crystal portion and the first dielectric layer.

12. A method for preparing a photonic crystal filter, comprising: providing a substrate base plate; Forming a first type of semiconductor doped layer thin film on the substrate; Applying a resist on the first type of semiconductor doped layer thin film and pre-curing it to form a resist layer; Performing nano-imprinting on the resist layer using an imprint template to transfer the pattern of the imprint template to the resist layer, and performing a curing treatment on the resist layer to form a resist layer pattern; The first type of semiconductor doped layer thin film is patterned using the resist layer pattern as a mask to form a photonic crystal layer, and the resist layer pattern is removed; wherein, The photonic crystal layer includes a photonic crystal portion, the photonic crystal portion includes a plurality of photonic crystal units arranged in an array, each of the photonic crystal units includes a plurality of through holes arranged in an array, each of the photonic crystal units includes a central region and a peripheral region surrounding the central region, the plurality of through holes include first through holes arranged in an array in the central region and second through holes arranged in an array in the peripheral region; The central area includes Na×Na first through holes, wherein Na is a positive integer greater than or equal to 5; The number of the second through holes on each side of the peripheral area is Na×Nb, where Nb is a positive integer greater than or equal to 1; The minimum distance between two adjacent first through holes is a first spacing Da, the minimum distance between two adjacent second through holes is a second spacing Db, the minimum distance between the first through hole and the second through hole is a third spacing Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

13. The preparation method according to claim 12, further comprising: forming an active layer thin film on the base substrate; A first dielectric layer thin film is formed between the active layer thin film and the photonic crystal layer; wherein, The active layer thin film is configured to emit light and serve as an optical gain medium.

14. The preparation method according to claim 13, further comprising: A second dielectric layer film is formed on a side of the photonic crystal layer away from the first dielectric layer film, wherein the material of the second dielectric layer film is a heavily doped material of a first type of semiconductor, and each of the through holes includes a first end and a second end opposite to each other along an extension direction of the channel thereof, the first end being connected to the first dielectric layer film, and the second end being connected to the second dielectric layer film.

15. A spectrum detection system, comprising: A semi-transparent and semi-reflective mirror, an objective lens, an imaging structure, a 4f optical system, and the photonic crystal filter according to any one of claims 1 to 11.

16. A spectrum detection method, comprising: Forming a spectrum to be measured with different characteristics; The spectrum to be measured is input into the spectrum detection system as claimed in claim 15 to distinguish the spectrum to be measured with different characteristics.

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