Photonic crystal optical filter and spectrum detection system

Abstract

A photonic crystal optical filter and a spectrum detection system, the photonic crystal optical filter comprising: a photonic crystal portion comprising a plurality of photonic crystal units, each photonic crystal unit comprising a plurality of through holes arranged in an array, each photonic crystal unit comprising 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 and a spectral detection system. BACKGROUND

[0002] Spectroscopy is an important method for characterizing the spectral features of light, and thus can be applied in fields such as agriculture, medicine, and communication. Due to the unique ability of miniature spectrometers for portability and on-site diagnosis, it has become an emerging field, which has made great progress by using dispersive or narrow-band optical elements and Fourier transform devices. In principle, photons can be spectrally distinguished by sufficiently different optical paths or lifetimes. Since the limited volume restricts the ability to expand the optical path, and narrow-band resonances are difficult to cover the entire required spectrum, achieving the best size, resolution, and range in miniature spectrometers requires complex trade-offs.

[0003] However, high spectral selective components, such as high quality factor (Q) value optical resonators, are essential for achieving high resolution and are also very advantageous. By arranging high Q value resonators into an array, the detection range can be expanded while maintaining a compact size using state-of-the-art nanofabrication techniques. Therefore, various miniaturized resonators such as nanowires, quantum dots, micro-ring resonators, and plasmonic metasurfaces have been used for parallel spectral detection. However, most resonant structures capable of generating high Q values require symmetry, and when fine structures are prepared, electron beam lithography (EBL) is used. When the resonant unit is larger than the EBL writing field size, mechanical errors, beam drift, and other problems often occur, resulting in a decrease in performance, so miniaturized device sizes are necessary. However, to achieve high resolution and wide detection range, the resonator array must be large-scale, which poses a huge challenge to connecting, scanning, and calibrating elements. Therefore, ultra-high Q value microcavities capable of out-of-plane excitation can be a very promising candidate, as they can avoid the need for planar coupling and time scanning like micro-ring resonator arrays. Therefore, while improving the performance of spectral detection, it is a challenging problem to design a high Q value microcavity array with the smallest possible unit volume to generate enough high Q value characteristic responses. CONTENT OF THE INVENTION

[0004] The photonic crystal filter and the spectrum detection system provided by the embodiments of the present disclosure can realize high-efficiency 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 a spectrum detection system, spectrum detection can be realized, and the precision of spectrum detection can be improved. Moreover, the spectrum detection system and the spectrum detection method provided by the embodiments of the present disclosure can have the advantages of process robustness, high precision, adjustable precision, and smaller size, and the like, which are beneficial to further realize a miniaturized spectrum detection system.

[0005] The photonic crystal filter provided by the embodiments of the present disclosure includes a photonic crystal part, and the photonic crystal part 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, and each photonic crystal unit includes a central region and a peripheral region surrounding the central region. The plurality of through holes include first through holes arranged in the central region and second through holes arranged in the peripheral region. The central region includes Na×Na first through holes, where Na is a positive integer greater than or equal to 5. The number of second through holes on each side of the peripheral region 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 pitch Da, the minimum distance between two adjacent second through holes is a second pitch Db, and the minimum distance between the first through holes and the second through holes is a third pitch Dg, and Na*Da+Nb*Db+Dg≤10 μm is satisfied.

[0006] For example, in the photonic crystal filter provided by the embodiments of the present disclosure, the minimum distance between two adjacent photonic crystal units is a fourth pitch Nag, and the fourth pitch 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 by at least one embodiment of the present disclosure, a transition region is further included between the center region and the peripheral region, the through holes further include third through holes arranged in an array in the transition region, the minimum distance between any two adjacent third through holes is a fifth pitch, the arrangement density of the first through holes is greater than that of the third through holes, and the arrangement density of the third through holes is greater than that of the second through holes, the first pitch is less than the fifth pitch, and the fifth pitch is less than the second pitch; or, the arrangement density of the first through holes is less than that of the third through holes, and the arrangement density of the third through holes is less than that of the second through holes, the first pitch is greater than the fifth pitch, and the fifth pitch is greater than the second pitch.

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

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

[0010] For example, in the photonic crystal filter provided by 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 center region is a square; the peripheral region includes four side regions and four corner regions, the shapes of the four side regions and the four corner regions are both rectangles; the long sides of each of the four side regions close to the center region are respectively aligned with the four sides of the center region and have equal lengths; the four corner regions are respectively located in the directions away from the center of the square at the four corners of the center region, and the lengths of the two adjacent sides of each of the four corner regions are respectively equal to the lengths of the two adjacent short sides of the two side regions adjacent thereto.

[0011] For example, in the photonic crystal filter provided by at least one embodiment of the present disclosure, the four side regions are all rectangular regions arranged by Na×Nb second through holes, the four corner regions are all square regions arranged 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 comprises an active layer and a first dielectric layer arranged between the active layer and the photonic crystal part, wherein the active layer is configured to emit light as a light gain medium.

[0013] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure further comprises a second dielectric layer arranged on a side of the photonic crystal part away from the first dielectric layer, wherein each of the through holes comprises opposite first and second ends along the extension direction of the channel thereof, the first end is connected with the first dielectric layer, and the second end is connected with the second dielectric layer.

[0014] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure further comprises an n-type substrate, an n-type semiconductor heavily doped layer and an n-type semiconductor doped layer arranged on the n-type substrate in sequence, a p-type semiconductor doped layer and a p-type semiconductor heavily doped layer arranged on a side of the active layer away from the n-type substrate in sequence, 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 apart 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 part and the first dielectric layer.

[0015] For example, the photonic crystal filter provided by at least one embodiment of the present disclosure further comprises an n-type substrate, an n-type semiconductor heavily doped layer and an n-type semiconductor doped layer arranged on the n-type substrate in sequence, a p-type semiconductor doped layer and a p-type semiconductor heavily doped layer arranged on a side of the active layer away from the n-type substrate in sequence, 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 apart 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 part and the first dielectric layer.

[0016] At least one embodiment of the present disclosure further provides a spectrum detection system, which comprises a half-transmission half-reflection mirror, an objective lens, an imaging structure, a 4f optical system, and the photonic crystal filter according to any one of the above embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0017] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0018] Figure 1 A block diagram of a photonic crystal filter provided in at least one embodiment of the present disclosure;

[0019] Figure 2 This is a schematic diagram of a planar structure of a photonic crystal section provided in at least one embodiment of the present disclosure;

[0020] Figure 3 for Figure 2 A partially magnified structural diagram of the central region of the photonic crystal section;

[0021] Figure 4 A schematic diagram of a planar structure of another photonic crystal section provided in at least one embodiment of the present disclosure;

[0022] Figure 5 for Figure 4 An enlarged structural diagram of region B, defined by the dashed line in the diagram;

[0023] Figure 6 A schematic diagram of a planar structure of a photonic crystal section provided in at least one embodiment of the present disclosure;

[0024] Figure 7 for Figure 6 A magnified structural diagram of the region C defined by the dashed line;

[0025] Figure 8 A schematic diagram of a planar structure of a photonic crystal section provided in at least one embodiment of the present disclosure;

[0026] Figure 9 for Figure 8 A magnified structural diagram of the region D defined by the dashed line;

[0027] Figure 10 A schematic diagram of a planar structure of a photonic crystal section provided in at least one embodiment of the present disclosure;

[0028] Figure 11 A schematic diagram showing a planar structure of multiple photonic crystal arrays and an enlarged structure of a single photonic crystal, provided in at least one embodiment of this disclosure;

[0029] Figure 12 A schematic cross-sectional view of a photonic crystal filter provided in at least one embodiment of this disclosure;

[0030] Figure 13 A schematic cross-sectional view of another photonic crystal filter provided in at least one embodiment of this disclosure;

[0031] Figure 14 A flowchart of a method of fabricating a photonic crystal filter according to at least one embodiment of the present disclosure;

[0032] Figures 15A-15E A process diagram of a method of fabricating a photonic crystal filter according to at least one embodiment of the present disclosure;

[0033] Figure 16 A flowchart of a method of fabricating a photonic crystal filter according to at least one embodiment of the present disclosure;

[0034] Figures 17A-17H A process diagram of a method of fabricating a photonic crystal filter according to at least one embodiment of the present disclosure;

[0035] Figure 18 A flowchart of a method of fabricating a photonic crystal filter according to at least one embodiment of the present disclosure;

[0036] Figures 19A-19I A process diagram of a method of fabricating a photonic crystal filter according to at least one embodiment of the present disclosure;

[0037] Figure 20 A block diagram of a spectral detection system according to at least one embodiment of the present disclosure;

[0038] Figure 21 A pattern of a photonic crystal microcavity array measured by a spectral detection system having a photonic crystal filter according to at least one embodiment of the present disclosure;

[0039] Figure 22 A loss curve diagram of a demodulation spectral neural network training process according to at least one embodiment of the present disclosure;

[0040] Figure 23 A demodulation spectral performance characterization diagram according to at least one embodiment of the present disclosure; and

[0041] Figure 24 A simulation performance diagram of a spectral detection system avoiding a field-of-view stitching problem according to at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present disclosure.

[0043] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the ordinary meaning as understood by a person having ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different components. The terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0044] The photonic crystal filter has the advantages of high power, high reliability, long service life, small size, high quality factor, small divergence angle, narrow spectral line width, applicability to multi-wavelength single-mode operation, and low cost, and is applied in various fields. For example, the inventors of the present disclosure have noticed that in the field of spectral detection, the photonic crystal part included in the spectral detection system usually has regular shape units, the size of the photonic crystal part can be smaller than the sub-field size of the commonly used electron beam exposure, each regular shape unit has multiple 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 are irrelevant, thereby effectively avoiding the coupling between adjacent units due to similar wavelengths.

[0045] The inventors of the present disclosure have 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 based on the optical path of the 4f optical system, in addition, a rich pattern can be generated under a very small array unit volume, which represents the high Q resonance peaks of different characteristic wavelengths generated by the structure to be detected, thereby achieving detection of the detected spectrum.

[0046] For example, Figure 1 A block diagram of a photonic crystal filter is provided for at least one embodiment of the present disclosure, as shown in Figure 1The photonic crystal filter 10 includes a photonic crystal section 100. The photonic crystal section 100 operates as follows: A bandgap structure is generated within the photonic crystal section 100 due to the periodic change in the refractive index of light. This bandgap structure controls the movement of light within the photonic crystal section; that is, low refractive index materials periodically appear at certain locations within the high refractive index material. The alternating arrangement of high and low refractive index materials to form a periodic structure generates a photonic crystal bandgap (similar to a band gap in semiconductors). Since the distance between the periodically arranged low refractive index sites is the same, the photonic crystal section with a certain distance only produces a bandgap effect for light waves of a certain frequency. In other words, only light of a certain frequency will be completely blocked from propagating within a photonic crystal with a certain periodic distance.

[0047] For example, Figure 2 This is a schematic diagram of a planar structure of a photonic crystal section provided in at least one embodiment of the present disclosure, as shown below. Figure 2 As shown, the photonic crystal section 100 includes a plurality of photonic crystal units arranged in an array, each photonic crystal unit including a plurality of through-holes 101 arranged in an array. Figure 2 In this example, we will use a circular planar shape for each through hole 101 as an example. Figure 2 In this embodiment, the diameter of each circle is equal, meaning that the planar dimensions of each through-hole 101 are equal. Of course, the embodiments of this disclosure are not limited to this. The planar shape of each through-hole 101 can also be elliptical, triangular, regular hexagonal, irregular shape, or a combination of multiple shapes. The embodiments of this disclosure do not limit this, as long as the through-holes 101 are arranged in an array and are easy to form using nanoimprinting.

[0048] It should be noted that when the planar shape of the through hole 101 is circular, the imprinting template used in the nano-imprinting process can imprint a circular pattern; when the planar shape of the through hole 101 is triangular, the imprinting template used in the nano-imprinting process can imprint a triangular pattern; when the planar shape of the through hole 101 is elliptical, the imprinting template used in the nano-imprinting process can imprint an elliptical pattern; and when the planar shape of the through hole 101 is a regular hexagon, the imprinting template used in the nano-imprinting process can imprint a regular hexagonal pattern, that is, according to the different planar shapes of the formed through holes 101, the shapes of the patterns that can be imprinted by the selected nano-imprinting template are different. For example, in the same photonic crystal part, a part of the through holes 101 and another part of the through holes 101 can also have different planar shapes or different planar sizes, and in the embodiments of the present disclosure, only a suitable nano-imprinting template needs to be selected according to the pattern of the through holes to be formed, and there are many types of nano-imprinting templates, which can easily meet different pattern requirements. The cost of the nano-imprinting template is low, and the photonic crystal part with different planar shapes or different planar sizes is only formed in one imprinting process, and other process conditions remain unchanged. However, for the commonly used electron beam exposure process, the time required for exposure is long, thereby reducing work efficiency and increasing production cost.

[0049] For example, Figure 2 For example, the shape of each through hole 101 is a cylinder, the planar shape of each through hole 101 is circular, and the diameters of each circle are 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. Hereinafter, the planar shape of each through hole 101 is circular as an example.

[0050] For example, in other examples, the shape of the through hole 101 can also be an elliptical cylinder, that is, the planar shape of each through hole 101 is elliptical, the major axis of each ellipse is equal, and the minor axis is also equal; the shape of the through hole 101 can also be a triangular prism, that is, the planar shape of each through hole 101 is triangular, and the three sides of any two triangles are equal. Of course, in other embodiments, the through hole 101 can also have other shapes, which are not limited in the embodiments of the present disclosure.

[0051] For example, as shown in Figure 2 For example, each photonic crystal unit includes a central region 102 and a peripheral region 103 surrounding the central region 102. Figure 2The center area 102 and the peripheral area 103 are both rectangular in shape, and the through hole 101 in the peripheral area 103 only surrounds the four edge areas of the through hole 101 in the center area 102, and does not surround the corner areas. Of course, the embodiments of the present disclosure are not limited thereto, and the center area 102 can also be surrounded at the corner areas, or the shape of the peripheral area 103 as a whole can not be a plurality of rectangles, but can also be a circular ring, a square ring, an ellipse, etc., as long as the energy of the center area 102 of the photonic crystal part can be inhibited from leaking from the peripheral area 103 or the energy of the center area 102 of the photonic crystal part can be controlled to radiate to the peripheral area 103.

[0052] For example, the peripheral area 103 is used to regulate and control the inhibition of energy leakage of the center area 102 or the control of the energy of the center area 102 radiating to the peripheral area 103, so as to realize the regulation and control of the frequency selection capability of the photonic crystal unit.

[0053] For example, as shown in Figure 2 , the plurality of through holes 101 includes first through holes 101a arranged in an array in the center area 102 and second through holes 101b arranged in an array in the peripheral area 103, the relative arrangement density of the first through holes 101a is different from the relative arrangement density of the second through holes 101b, and in Figure 2 , the relative arrangement density of the first through holes 101a is greater than the relative arrangement density of the second through holes 101b.

[0054] For example, Figure 3 , the first through holes 101a are formed in the area A defined by the dashed line in Figure 2 , as shown in Figure 3 , the first through holes 101a are formed by nanoimprinting, and the first through holes 101a are arranged in a matrix, i.e., the first through holes 101a are arranged in the X-axis direction and the Y-axis direction respectively, and the plane defined by the X-axis and the Y-axis is the plane on which the top surface of the first through holes 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, i.e., the extension direction of the through hole 101. The area A defined by the dashed line includes the first through holes 101a and the second through holes 101b, as shown in Figure 3 , the minimum distance between any two adjacent first through holes 101a is the first pitch Da. It should be noted that the minimum distance between any two adjacent first through holes 101a refers to the minimum size among different sizes of any two adjacent first through holes 101a in different directions. In Figure 3In some embodiments, the distance between any two adjacent first through holes 101a in the first direction X is smaller than the distance between any two adjacent first through holes 101a in the second direction Y, i.e., the minimum distance between any two adjacent first through holes 101a in the first direction X is Da.

[0055] For example, in some embodiments, the distance between any two adjacent first through holes 101a in the first direction X is gradually reduced from the peripheral region 103 to the central region 102, and the distance between any two adjacent first through holes 101a in the second direction Y is gradually reduced from the peripheral region 103 to the central region 102. Figure 3 In some embodiments, the minimum distance between any two adjacent second through holes 101b is the second pitch 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 in different directions, and the minimum size among these different sizes is the minimum distance between any two adjacent second through holes 101b. Figure 3 In some embodiments, the distance between any two adjacent second through holes 101b in the second direction Y is smaller than the distance between any two adjacent second through holes 101b in the first direction X, i.e., the minimum distance between any two adjacent second through holes 101b in the second direction Y is Db, and in Figure 3 In some embodiments, 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 pitch Da is smaller than the second pitch Db.

[0056] For example, in some embodiments, the column of first through holes 101a close to the right side in the left dashed box and Figure 3 In some embodiments, the column of second through holes 101b close to the left side in the right dashed box and Figure 3 In some embodiments, any two adjacent first through holes 101a and second through holes 101b are arranged adjacent to each other, and the minimum distance between any two adjacent first through holes 101a and second through holes 101b is a third pitch Dg, which is greater than the first pitch Da and smaller than the second pitch Db, i.e., along the direction from the peripheral region 103 to the central region 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.

[0057] It should be noted that in other variations of Figure 3 In some embodiments, in the first direction X, along the direction from the peripheral region 103 to the central region 102, the distance between adjacent first through holes 101a gradually decreases, and the distance between adjacent second through holes 101b also gradually decreases, so that in the first direction X, along the direction from the peripheral region 103 to the central region 102, the distance between adjacent through holes 101 (including first through holes 101a and second through holes 101b) gradually decreases.

[0058] Specifically, in combination with Figure 2 and Figure 3, the center region 102 includes Na×Na first through holes 101a, where Na is a positive integer greater than or equal to 5; the number of second through holes 101b on each side of the peripheral region 103 is Na*Nb, where Nb is a positive integer greater than or equal to 1; the minimum distance between adjacent two first through holes 101a is a first pitch Da, the minimum distance between adjacent two second through holes 101b is a second pitch Db, and the minimum distance between the first through hole and the second through hole is a third pitch Dg, and satisfies Na*Da+Nb*Db+Dg≤10μm, where, in the peripheral regions on the left and right sides, Nb is the number of columns of second through holes 101b in the peripheral region 103; in the peripheral regions on the top and bottom sides, Nb is the number of rows of second through holes 101b in the peripheral region 103. That is, the above-mentioned Na, Nb, first pitch Da, second pitch Db and third pitch Dg in the center region of the photonic crystal part prepared by the nanoimprint method in the embodiment of the present disclosure are fluctuated, and under the condition of the above-mentioned data limit, the photonic crystal part can be prepared by using the nanoimprint technology to reduce the production cost and improve the production efficiency on the basis of ensuring high robustness and high quality factor (Q value), and is suitable for large-scale production, and when applied to a spectrum detection system, the precision and efficiency of spectrum detection can be improved.

[0059] For example, due to the fine structure of the photonic crystal filter provided by the embodiment of the present disclosure, when Na, Da, Nb, Db and Dg satisfy the above relationship, it is still necessary to finely design the structure parameters to achieve the required optical properties. The 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 a certain relationship to form the required resonance characteristics.

[0060] For example, by optimizing the above-mentioned structure parameters, a high quality factor (Q value) and a narrow linewidth resonance mode can be obtained, which is crucial for realizing 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 formed spectrum detection system has stable working characteristics near the target wavelength, so that the spectrum detection system is more reliable in actual application.

[0061] The embodiments disclosed herein require meticulous design of multiple parameters, thus increasing the complexity of the design process. It necessitates considering and precisely controlling the interrelationships between multiple variables to ensure that the photonic bandgap and resonant wavelength fall within the target range. Typically, the structural design of through-holes in photonic crystal filters requires nanometer-level fabrication precision and involves multiple simulations and experimental iterations to verify the design's rationality. Furthermore, due to limitations in fabrication equipment and process conditions, error accumulation may occur in actual production, affecting the design accuracy of the photonic crystal filter. Therefore, the design of photonic crystal filters must not only meet theoretical requirements but also consider the feasibility of the fabrication process, further increasing the design difficulty and challenges.

[0062] For example, in one example, the number of photonic crystal units arranged in the array is 400, the first spacing Da ranges from 522nm to 540nm, the second spacing Db ranges from 552nm to 570nm, the third spacing Dg ranges from 532nm to 550nm, Na is 7, and Nb is 6.

[0063] For example, Figure 4 This is a schematic diagram of the planar structure of another photonic crystal section provided in at least one embodiment of the present disclosure, as shown below. Figure 4 As shown, the photonic crystal section 100 includes a central region 102 and a peripheral region 103 surrounding the central region 102. For example, Figure 4 This explanation also uses the example of rectangular planar shapes for both the central region 102 and the outer region 103. The through-hole 101 in the outer region 103 only surrounds the four sides of the through-hole 101 located in the central region 102, leaving the corner areas unsurrounded. Figure 4 In the process, multiple through holes 101 include a first through hole 101a arranged in an array in the central region 102 and a second through hole 101b arranged in an array in the peripheral region 103. The relative arrangement density of the first through hole 101a is less than the relative arrangement density of the second through hole 101b.

[0064] 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 hole 101a refers to the number of the first through hole 101a per unit area, and the relative arrangement density of the second through hole 101b refers to the number of the second through hole 101b per unit area. When the shape or size of the first through hole 101a and the second through hole 101b is different, the planar area of the first through hole 101a and the second through hole 101b is equivalent to each other, for example, when the planar area of one first through hole 101a is equivalent to the planar area of two second through holes 101b, the relative arrangement density of the first through hole 101a refers to twice the number of the first through hole 101a per unit area, and the relative arrangement density of the second through hole 101b refers to the number of the second through hole 101b per unit area, or when the planar area of one first through hole 101a is equivalent to the planar area of 0.5 second through holes 101b, the relative arrangement density of the first through hole 101a refers to the number of the first through hole 101a per unit area, and the relative arrangement density of the second through hole 101b refers to twice the number of the second through hole 101b per unit area. That is, when the planar area of one 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 hole 101a refers to n times the number of the first through hole 101a per unit area, and the relative arrangement density of the second through hole 101b refers to the number of the second through hole 101b per unit area; when n is greater than 0 and less than 1, the planar area of one first through hole 101a is equivalent to the planar area of n second through holes 101b, the relative arrangement density of the first through hole 101a refers to the number of the first through hole 101a per unit area, and the relative arrangement density of the second through hole 101b refers to 1 / n times the number of the second through hole 101b per unit area.

[0065] For example, in one example, although Figure 2 and Figure 4 the relative arrangement densities of the first through hole 101a and the second through hole 101b are different, Figure 2 and Figure 4 the first through hole 101a and the second through hole 101b in may also be completed in the same nano-imprinting process step, without increasing the production cost.

[0066] For example, Figure 5 is Figure 4 an enlarged structural schematic view of the dashed line defined area B in , which includes the first through hole 101a and the second through hole 101b, as shown in 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 refers to the smallest of the different dimensions along different directions that exists between them. Figure 5 In the first direction X, the distance between two adjacent first through holes 101a is less 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.

[0067] For example, in Figure 5 In this context, 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 refers to the smallest of the different dimensions along different directions that exists between any two adjacent second through holes 101b. Figure 5 In the second direction Y, the distance between two adjacent second through holes 101b is less 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 in Figure 5 In the process, the relative arrangement density of the first through hole 101a is less than the relative arrangement density of the second through hole 101b, and the first spacing Da is greater than the second spacing Db.

[0068] For example, in Figure 5 In the middle, the second through hole 101b near the right side of the left dashed box and Figure 5 In the right dashed box, the first through holes 101a in the column near the left are respectively arranged adjacently. The minimum distance between any two adjacent first through holes 101a and second through holes 101b is the third spacing Dg, which is greater than the second spacing Db and less than the first spacing Da.

[0069] For example, in Figure 5 In this context, 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 both the first and second directions. This direction is determined based on the arrangement of adjacent first through holes 101a and second through holes 101b.

[0070] It should be noted that, in Figure 5In other variations of the above, the spacing between adjacent first through holes 101a in the first direction X along the direction from the peripheral region 103 to the central region 102 can gradually increase, and the spacing between adjacent second through holes 101b in the first direction X along the direction from the peripheral region 103 to the central region 102 can gradually increase, except that the distance between adjacent first through holes 101a and second through holes 101b in the first direction X along the direction from the peripheral region 103 to the central region 102 is not the spacing between adjacent first through holes 101a in the first direction X along the direction from the peripheral region 103 to the central region 102, i.e. the distance between adjacent first through holes 101a in the first direction X along the direction from the peripheral region 103 to the central region 102 is not the spacing between adjacent second through holes 101b in the first direction X along the direction from the peripheral region 103 to the central region 102. Figure 5 In other variations of the above, the spacing between adjacent first through holes 101a in the first direction X along the direction from the peripheral region 103 to the central region 102 can gradually increase, and the spacing between adjacent second through holes 101b in the first direction X along the direction from the peripheral region 103 to the central region 102 can gradually increase, except that the distance between adjacent first through holes 101a and second through holes 101b in the first direction X along the direction from the peripheral region 103 to the central region 102 is not the spacing between adjacent first through holes 101a in the first direction X along the direction from the peripheral region 103 to the central region 102, i.e. the distance between adjacent first through holes 101a in the first direction X along the direction from the peripheral region 103 to the central region 102 is not the spacing between adjacent second through holes 101b in the first direction X along the direction from the peripheral region 103 to the central region 102.

[0071] For example, Figure 6 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 6 For example, Figure 6 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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.

[0072] For example, Figure 7 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 6 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 6 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 7 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 6 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 7 For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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.

[0073] For example, as shown in FIG. 1C, the planar structure of the photonic crystal part 100 provided by at least one embodiment of the present disclosure 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. Figure 7As shown, the minimum distance between the adjacent third via hole 101c and the first via hole 101a is a sixth interval d6, the minimum distance between the adjacent third via hole 101c and the second via hole 101b is a seventh interval d7, the sixth interval d6 is smaller than the fifth interval d5 and larger than the first interval Da, the seventh interval d7 is larger than the fifth interval d5 and smaller than the second interval Db, which can make the peripheral region and the transition region sufficiently wrap the central region, the periodicity of the third via hole 101c in the transition region, the periodicity of the second via hole 101b in the peripheral region and the periodicity of the first via hole 101a in the central region are all different, so that the transition region further blocks the energy leakage or radiation in the two-dimensional photonic crystal microcavity, so as to more sufficiently inhibit the energy leakage from the peripheral region in the two-dimensional photonic crystal microcavity or control the energy radiation from the two-dimensional photonic crystal microcavity to the peripheral region, and the robustness is improved.

[0074] For example, the distance between the third via hole 101c in the transition region is set to the above size range, which can meet the application requirements of different scenes.

[0075] For example, Figure 8 Another planar structure schematic diagram of a photonic crystal part provided by at least one embodiment of the present disclosure is as shown in Figure 8 As shown, the photonic crystal part 100 includes a central region 102 and 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 planar shape of the central region 102, the transition region 104 and the peripheral region 103 is taken as an example of rectangle for illustration, the via hole 101 in the peripheral region 103 only surrounds the four edge regions of the via hole in the central region 102, and does not surround the corner region. Of course, the embodiments of the present disclosure are not limited thereto, and the central region can also be surrounded at the corner region.

[0076] For example, Figure 9 For Figure 8 The enlarged structure schematic diagram of the dashed area D in FIG. 10 is as shown in Figure 8 and Figure 9 As shown, the via hole 101 further includes third via holes 101c arranged in an array in the transition region 104, the minimum distance between any two adjacent third via holes 101c is a fifth interval d5, the minimum distance between any two adjacent first via holes 101a is a first interval Da, and the minimum distance between any two adjacent second via holes 101b is a second interval Db. For example, in Figure 8 and Figure 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 distance Da is greater than the fifth distance d5, and the fifth distance d5 is greater than the second distance Db.

[0077] For example, as shown in Figure 9 , the minimum distance between adjacent third through holes 101c and first through holes 101a is the sixth distance d6, the minimum distance between adjacent third through holes 101c and second through holes 101b is the seventh distance d7, the sixth distance d6 is greater than the fifth distance d5 and less than the first distance Da, and the seventh distance d7 is less than the fifth distance d5 and greater than the second distance Db.

[0078] For example, in Figure 9 , the first distance Da, the second distance Db, the fifth distance d5 and the seventh distance d7 are distances in the first direction X, the sixth distance d6 is a distance in a direction having a certain angle with the first direction X and the second direction Y in the plane formed by the first direction X and the second direction Y, and the direction is determined according to the arrangement of adjacent third through holes 101c and first through holes 101a.

[0079] For example, in Figure 6 , Figure 7 , Figure 8 and Figure 9 , the plane shapes and plane sizes of the first through holes 101a, the second through holes 101b and the third through holes 101c are the same, and in Figure 6 , Figure 7 , Figure 8 and Figure 9 , the shapes of the through holes 101 are cylindrical and the plane shapes are circular, which are examples for description. For other shapes or sizes of the through holes 101, the above-mentioned distances can be set according to the above description, which will not be described here.

[0080] For example, Figure 10 , another plane structure of the photonic crystal part provided by at least one embodiment of the present disclosure is shown in Figure 10As shown, the first through holes 101a are arranged in a matrix, and the overall outer contour shape of the matrix-arranged first through holes 101a is a quadrilateral. The second through holes 101b are arranged on the side of each side of the quadrilateral away from the center of the central region 102, and the second through holes 101b surround the overall matrix-arranged first through holes 101a, so that the periphery of the matrix formed by the first through holes 101a is surrounded by the second through holes 101b, thereby more fully inhibiting energy leakage from the peripheral region 103 in the two-dimensional photonic crystal microcavity or controlling the radiation of energy in the two-dimensional photonic crystal microcavity to the peripheral region 103.

[0081] For example, as shown in FIG. 1, the first through holes 101a form a square array, and the planar shape of the central region 102 is a square. The peripheral region 103 includes four edge regions 103a and four corner regions 103b, and the shape of each of the four edge regions 103a and the four corner regions 103b is a rectangle. The long side of each of the four edge regions 103a close to the central region 102 is aligned with the four sides of the central region 102 and has the same length. The four corner regions 103b are located in the direction away from the center of the square at the four corners of the central region 102, and the adjacent two sides of each of the four corner regions 103b are aligned with the adjacent two short sides of the two edge regions 103a close to the corner regions 103b and have the same length. Figure 10 For example, as shown in FIG. 1, the four edge regions 103a are each a rectangular region arranged by Na×Nb second through holes 101b, and the four corner regions 103b are each a rectangular region arranged by Nb×Nb second through holes 101b. Na and Nb are both positive integers, and Na is greater than Nb. For example, in the embodiment shown in FIG. 1, Na is 12, and Nb is 4. The central region 102 includes 12*12 first through holes 101a, the edge region 103a includes 12*4 second through holes 101b, and the corner region 103b includes 4*4 second through holes 101b. Of course, the embodiments of the present disclosure are not limited thereto, and Na and Nb can also be other values. Na can also be less than Nb, or Na can be equal to Nb.

[0082] Figure 10 For example, as shown in FIG. 1, the four edge regions 103a are each a rectangular region arranged by Na×Nb second through holes 101b, and the four corner regions 103b are each a rectangular region arranged by Nb×Nb second through holes 101b. Na and Nb are both positive integers, and Na is greater than Nb. For example, in the embodiment shown in FIG. 1, Na is 12, and Nb is 4. The central region 102 includes 12*12 first through holes 101a, the edge region 103a includes 12*4 second through holes 101b, and the corner region 103b includes 4*4 second through holes 101b. Of course, the embodiments of the present disclosure are not limited thereto, and Na and Nb can also be other values. Na can also be less than Nb, or Na can be equal to Nb. Figure 10

[0083] ​​It should be noted that the size of the first via hole 101a in the center region 102, the first interval Da between two adjacent first via holes 101a, and the value of Na can be changed. The size, number of the second via holes 103b in the four edge regions 103a and the four corner regions 103b, and the second interval Db between adjacent second via holes 103b can be adjusted, and by adjusting the above-mentioned features in the edge regions 103a and the corner regions 103b, the energy leakage from the edge regions 103a and the corner regions 103b in the microcavity included in the photonic crystal filter or the control of the energy radiation to the edge regions 103a and the corner regions 103b in the microcavity included in the photonic crystal filter can be achieved.

[0084] For example, in one example, by adjusting at least one of the second interval Db between adjacent second via holes 103b in the edge regions 103a and the corner regions 103b, the size of the second via holes 103b in the peripheral region, and the interval between the edge regions 103a and the corner regions 103b and the center region 102, the band gap of the microcavity included in the photonic crystal filter can be formed, so as to confine the energy in the center region 102 and suppress the leakage of the side energy of the microcavity.

[0085] For example, in one example, by adjusting the size and / or distance between adjacent second via holes 103b in the edge regions 103a and the corner regions 103b corresponding to any direction of the side edge, the leakage of the energy in the microcavity included in the photonic crystal filter can be controlled, so as to achieve the radiation of the energy in the microcavity included in the photonic crystal filter to any direction of the side edge.

[0086] For example, in one example, by adjusting the number of second via holes 103b in the edge regions 103a and the corner regions 103b corresponding to any direction of the side edge, such as removing part of the second via holes 103b, the leakage of the energy in the microcavity included in the photonic crystal filter in that direction can be controlled, so as to achieve the radiation of the energy in the microcavity included in the photonic crystal filter to any direction of the side edge.

[0087] For example, in the structure design of the photonic crystal part 100 in the embodiment of the present disclosure, the energy radiation on the upper and lower surfaces of the photonic crystal part 100 and the leakage of the side energy can be suppressed, the energy can be confined in the microcavity included in the photonic crystal filter, and the quality factor Q of the photonic crystal filter can be improved. At the same time, by destroying part of the 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 coupling of the energy in the microcavity included in the photonic crystal filter and the energy of the optical structure outside the microcavity.

[0088] For example, Figure 11This is a schematic diagram illustrating the planar structure of a plurality of photonic crystal arrays and the enlarged structure of a single photonic crystal unit provided in at least one embodiment of this disclosure, as shown below. Figure 11 As shown, the minimum distance between two adjacent photonic crystal units is the fourth spacing Nag, which is greater than or equal to 5 micrometers and less than or equal to 10 micrometers. Although in Figure 11 The illustration shows 16 photonic crystal units arranged in an array, but the embodiments of this disclosure are not limited to this; there may be more or fewer photonic crystal units arranged in an array. For example, in Figure 11 The enlarged structural schematic diagram of a single photonic crystal section also shows the first spacing Da, the second spacing Db, the third spacing Dg, as well as Na and Nb. Each photonic crystal section satisfies the aforementioned condition Na*Da+Nb*Db+Dg≤10μm. This allows the photonic crystal filter to improve the accuracy of spectral detection when used in a spectral detection system.

[0089] For example, Figure 12 This is a schematic cross-sectional view of a photonic crystal filter provided in at least one embodiment of the present disclosure, as shown below. Figure 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 section 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.

[0090] For example, such as Figure 12 As shown, the photonic crystal filter 10 further includes a second dielectric layer 107 disposed on the side of the photonic crystal section 100 away from the first dielectric layer 106. Each through-hole 101 (including a first through-hole 101a and a second through-hole 101b) includes opposing first and second ends along its channel extension direction. The first end is connected to the first dielectric layer 106, and the second end is connected to the second dielectric layer 107. That is, the first dielectric layer 106 and the second dielectric layer 107 close 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 hole transport or electron transport functions.

[0091] For example, such as Figure 12 As shown, the through-hole 101 is filled with a medium of refractive index n0, which can be a gas (e.g., air), solid, or liquid material. In one example, the medium filling the through-hole 101 can also be the same medium as the material of the photonic crystal section 100.

[0092] For example, in one example, the medium filled in the through hole 101 can be at least one of silicon, germanium, a germanium silicon material, a compound of silicon, a compound of germanium, a metal, or a III-V material, the compound of silicon includes at least one of silicon nitride, silicon dioxide, silicon carbide, and when the photonic crystal part is a double layer or a multi-layer, at least one layer is not through.

[0093] Embodiments of the present disclosure do not limit the size relationship of 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 indexes according to needs, and embodiments of the present disclosure do not limit this.

[0094] For example, in combination with the above-mentioned embodiments of the present disclosure, Figure 12 For example, in one example, the medium filled in the through hole 101 can be at least one of silicon, germanium, a germanium silicon material, a compound of silicon, a compound of germanium, a metal, or a III-V material, the compound of silicon includes at least one of silicon nitride, silicon dioxide, silicon carbide, and when the photonic crystal part is a double layer or a multi-layer, at least one layer is not through.

[0095] For example, in embodiments 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 needed, for example, in one example, the lower half of the through hole 101 can be selected to be filled or only one side of the through hole 101 can be filled, or the through hole 101 can be filled in other arbitrary filling modes. The materials of the first medium layer 106, the photonic crystal part 100, and the second medium layer 107 and the material of the medium filled in the through hole 101 can be materials with or without optical gain.

[0096] For example, as shown in the above-mentioned embodiments of the present disclosure, Figure 12 For example, as shown in the above-mentioned embodiments of the present disclosure,

[0097] For example, in the above-mentioned embodiments of the present disclosure, Figure 12In the illustrated structure, the photonic crystal part 100 and the first dielectric layer 106 are formed in the same process step and are integrally formed by the p-type semiconductor doped layer 204. It should be noted that if a layer of the first dielectric layer 106 is not reserved under the photonic crystal part 100 so that the p-type semiconductor doped layer 204 is not penetrated, damage to the active layer 105 can occur in the process of forming the photonic crystal part 100, which can weaken the light emission and light gain performance of the active layer 105.

[0098] 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 formed by bonding or flip-chip bonding a layer structure formed by GaAs, InP, GaSb, or GaN on a Si substrate.

[0099] For example, the structure of the active layer 105 includes a quantum well, a quantum wire, or a quantum dot; 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 light gain, with the gain spectrum peak wavelength range covering the ultraviolet to far infrared band.

[0100] For example, the material of the n-type electrode layer 207 includes a metal such as Au, AuGe, AuGe / Au, AuGeNiAu, a metal alloy, or a transparent conductive material such as indium tin oxide (ITO).

[0101] For example, the material of the p-type electrode layer 206 includes, but is not limited to, a metal such as Au, Ti, Pt, Cr, a metal alloy such as TiPtAu, AuZnAu, NiAg, or CrAu. For example, the p-type electrode layer 206 can be prepared by a lift-off 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 gas or hydroiodic acid gas, in addition, argon gas, xenon gas, or inert gas is mixed into the chlorine gas or hydroiodic acid gas, and the ratio between the chlorine gas or hydroiodic acid gas and the inert gas is about 2:1.

[0102] For example, the p-type semiconductor heavily doped layer 205 is formed on the photonic crystal part 100 by epitaxial growth or bonding.

[0103] For example, the materials of the other layer structures of the photonic crystal filter 10 can be selected according to conventional materials, and embodiments of the present disclosure are not limited in this regard. The thicknesses of the various layer structures of the photonic crystal filter 10 can be selected according to conventional design, and embodiments of the present disclosure are not limited in this regard.

[0104] Note that the via hole 101 can also be formed in the p-type semiconductor heavily doped layer 205 as the photonic crystal portion 100.

[0105] For example, Figure 12 The operation method of the photonic crystal filter 10 shown includes that 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 the holes and the 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 band gap of the semiconductor layer included in the active layer 105.

[0106] For example, the p-type semiconductor heavily doped layer 205, the photonic crystal layer 204 to the n-type semiconductor heavily doped layer 202 constitute a multilayer dielectric layer structure, and the light emitted in the active layer 105 excites a dielectric layer optical mode, a part of which is evanescent light reaching the photonic crystal portion 100, and diffracts with the periodic structure of the photonic crystal portion 100. When the wavelength of the optical mode has a defined matching relationship with the period of the photonic crystal in the photonic crystal portion 100, the layered structure and the photonic crystal generate a stable resonant mode, which becomes a laser oscillation mode.

[0107] For example, Figure 13 Another cross-sectional structure of a photonic crystal filter is provided for at least one embodiment of the present disclosure, as shown in Figure 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 arranged on the n-type substrate 201 in sequence, a p-type semiconductor doped layer 204 and a p-type semiconductor heavily doped layer 205 arranged on the active layer 105 away from the n-type substrate 201 in sequence, a p-type electrode layer 206 arranged on the p-type semiconductor heavily doped layer 205 away from the n-type substrate 201, and an n-type electrode layer 207 arranged on the n-type semiconductor heavily doped layer 202 away from the n-type substrate 201 and spaced apart from the n-type semiconductor doped layer 203; the active layer 105 is arranged on 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.

[0108] For example, in Figure 13In the structure shown, a first dielectric layer 106 needs to be specially arranged between the photonic crystal part 100 and the active layer 105, which can also be formed of n-type semiconductor doped material, to prevent the material of the active layer 105 from filling the through hole 101 in the photonic crystal part 100 in the process of forming the active layer 105 after the photonic crystal part 100 with the through hole 101 is formed. In addition, if a first dielectric layer 106 is not specially arranged between the n-type semiconductor doped layer 203 and the active layer 105, it is also not conducive to the epitaxial growth of the active layer 105.

[0109] For example, Figure 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 the 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 constitute a multilayer dielectric layer structure, and the light emitted in the active layer 105 excites a dielectric layer optical mode, a part of which is evanescent light that 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 designed period of the photonic crystal in the photonic crystal part 100, the layered structure and the photonic crystal produce a stable resonant mode, which becomes a laser emission mode.

[0111] For example, Figure 13 The materials and thicknesses of the various layer structures included in the photonic crystal filter 10 shown can refer to the related descriptions in the above Figure 12 , which will not be described here again.

[0112] For example, in the embodiments of the present disclosure, Figure 12 and Figure 13 The photonic crystal filter 10 shown includes a single-mode photonic crystal filter and a multi-mode photonic crystal filter.

[0113] The preparation method of the photonic crystal filter provided by at least one embodiment of the present disclosure includes the following steps.

[0114] For example, Figure 14 A flowchart of a preparation method of a photonic crystal filter provided by at least one embodiment of the present disclosure is shown in Figures 15A-15E The preparation method includes the following steps.

[0115] S11: providing a substrate substrate.

[0116] S12: forming a first type of semiconductor doped layer film on the substrate substrate.

[0117] S13: applying a resist on the first type of semiconductor doped layer film and performing a pre-curing process to form a resist layer.

[0118] S14: performing nanoimprinting on the resist layer by using a stamping template to transfer the pattern of the stamping template to the resist layer and performing a curing process to form a resist layer pattern.

[0119] S15: performing a patterning process on the first type of semiconductor doped layer film to form a photonic crystal layer with the resist layer pattern as a mask, and removing the resist layer pattern, wherein the photonic crystal layer comprises a photonic crystal part, the photonic crystal part comprises a plurality of photonic crystal units arranged in an array, 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 surrounding the central region, the plurality of through holes comprises a first through hole arranged in the central region and a second through hole arranged in the peripheral region; the central region comprises 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 region 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 pitch Da, the minimum distance between two adjacent second through holes is a second pitch Db, and the minimum distance between the first through hole and the second through hole is a third pitch Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

[0120] For example, Figure 15A A process diagram of a preparation method of a photonic crystal filter is provided for at least one embodiment of the present disclosure.

[0121] As Figure 15B shown, a substrate wafer 301 is provided, which can be an n-type substrate, the material of the n-type substrate including but not limited to GaAs, InP, GaSb or GaN, or the n-type substrate can also be a substrate wafer formed by bonding or flip-chip bonding a layer structure formed of GaAs, InP, GaSb or GaN on a Si substrate.

[0122] For example, processing the substrate wafer 301 includes cleaning and surface treatment of the substrate wafer 301 to ensure the flatness and cleanliness of the surface of the substrate wafer 301.

[0123] For example, as Figure 15C shown, a first type of semiconductor doped layer film 302 is formed on the substrate wafer 301. For example, the first type of semiconductor doped layer film 302 can be an n-type semiconductor doped layer film or a p-type semiconductor doped layer film. For example, the first type of semiconductor doped layer film 302 can be formed by epitaxial growth.

[0124] For example, the first type of semiconductor doped layer film 302 can be applied on the substrate wafer 301 by a spin coater or a coating machine and the like, which can make the glue solution uniformly coated on the surface of the substrate wafer and control the thickness and uniformity of the first type of semiconductor doped layer film 302.

[0125] For example, as Figure 15DAs shown, a resist is applied on the first type of semiconductor doped layer thin film 302, and a pre-curing process is performed to form a resist layer 303. For example, the resist can be applied on the first type of semiconductor doped layer thin film 302 in a liquid state, and then a pre-curing process is performed to make the resist in a non-free flowing state, i.e. in a semi-solid state, so that the subsequent imprinting template 304 can transfer its pattern to the resist layer 303. For example, the pre-curing process of the resist can include a method of irradiation by ultraviolet light or a method of temperature reduction curing.

[0126] For example, as shown in Figure 15D , a nano-imprinting process is performed on the resist layer 303 by using the imprinting template 304 to transfer the pattern of the imprinting template 304 to the resist layer 303, and a curing process is performed to form a resist layer pattern 305. That is, the process of transferring the pattern of the imprinting template 304 to the resist layer 303 is completed in Figure 15E . For example, the part of the first type of semiconductor doped layer thin film covered by the resist layer pattern 305 is the reserved part of the first type of semiconductor doped layer thin film, and the part not covered is the etched part. For example, the nano-imprinting technology can include an ultraviolet nano-imprinting technology or a thermal nano-imprinting technology. For example, the curing method of the resist layer 303 can include a method of irradiation by ultraviolet light or a method of temperature reduction curing.

[0127] For example, in one example, the nano-imprinting technology of the resist layer 303 is an ultraviolet nano-imprinting technology, and the curing method of the resist layer 303 is a method of irradiation by ultraviolet light; in another example, the nano-imprinting technology of the resist layer 303 is a thermal nano-imprinting technology, and the curing method of the resist layer 303 is a method of temperature reduction curing.

[0128] For example, as shown in Figures 2-11 , a patterning process is performed on the first type of semiconductor doped layer thin film 302 to form a photonic crystal layer by using the resist layer pattern 305 as a mask, and the resist layer pattern 305 is removed, and the planar structure of the photonic crystal part 100 included in the photonic crystal layer can refer to the above Figure 15E , which will not be repeated here.

[0129] It should be noted that in Figure 16 , the part of the first type of semiconductor doped layer thin film 302 close to the substrate 301 is reserved as the first dielectric layer, and in other embodiments, the first type of semiconductor doped layer thin film 302 can be etched through, and the part of the first type of semiconductor doped layer thin film 302 close to the substrate 301 is not reserved.

[0130] For example, it is also necessary to point out that the first type of semiconductor doped layer film can be a first type of semiconductor heavily doped layer film.

[0131] For example, the patterning process includes steps such as exposure, development, etching and de-gluing, specifically, after the deposited film layer is subjected to proximity effect correction (PEC), the chip after uniform coating is placed into an electron beam exposure machine or a photoetching machine, then an electron beam is scanned or passes through a mask to the surface of the glue layer to form the required pattern. The exposed photoresist is then chemically treated so that the photoresist dissolves or solidifies in the developing solution, thereby forming the required pattern. Etching and de-gluing include using chemical or physical methods to completely remove the unexposed glue layer from the surface of the substrate, while protecting the glue layer in the exposed area from being affected, exposing the underlying substrate or the bottom photonic crystal structure, and then using a suitable solvent or chemical solution to dissolve or remove the remaining photoresist, to ensure the integrity and clarity of the photonic crystal layer structure.

[0132] For example, Figure 16 Another flowchart of a preparation method of a photonic crystal filter is provided for at least one embodiment of the present disclosure, as shown in Figures 17A-17H The preparation method includes the following steps.

[0133] S21: A substrate is provided, and a second type of semiconductor heavily doped layer film, a second type of semiconductor doped layer film, an active layer film and a first type of semiconductor doped layer film are sequentially formed on the substrate.

[0134] S22: A resist is applied to the first type of semiconductor doped layer film, and a pre-curing treatment is performed to form a resist layer.

[0135] S23: Nanoimprinting is performed on the resist layer using an imprinting template to transfer the pattern of the imprinting template to the resist layer, and a curing treatment is performed to form a resist layer pattern.

[0136] S24: performing a patterning process on the first type of semiconductor doped layer film to form a photonic crystal layer and a first dielectric layer film with the resist layer pattern as a mask, and removing the resist layer pattern, wherein the first dielectric layer film is on a side of the photonic crystal layer close to the substrate, the photonic crystal layer comprises a plurality of through holes arranged in an array, the photonic crystal layer comprises a photonic crystal part, the photonic crystal part comprises a plurality of photonic crystal units arranged in an array, 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 surrounding the central region, the plurality of through holes comprises a first through hole arranged in the central region and a second through hole arranged in the peripheral region; the central region comprises 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 region 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 pitch Da, the minimum distance between two adjacent second through holes is a second pitch Db, and the minimum distance between the first through hole and the second through hole is a third pitch Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

[0137] S25: sequentially forming a first type of semiconductor heavily doped layer film, a hard mask and a photoresist layer on a side of the photonic crystal layer away from the substrate.

[0138] S26: performing patterning on the photoresist layer to form a photoresist pattern covering a preset region, performing patterning on the hard mask with the photoresist pattern as a mask and removing the photoresist pattern to form a hard mask pattern.

[0139] S27: performing a patterning process on the first type of semiconductor heavily doped layer film, the photonic crystal layer, the first dielectric layer film, the active layer film and the second type of semiconductor doped layer film with the hard mask pattern as a mask to form a second dielectric layer, a photonic crystal part, a first dielectric layer, an active layer and a second type of semiconductor doped layer, respectively, and a gap exists 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.

[0140] 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 in the gap on a side of the second type of semiconductor heavily doped layer film away from the substrate.

[0141] For example, Figure 17A A process diagram of a preparation method of a photonic crystal filter is provided for at least one embodiment of the present disclosure.

[0142] For example, as Figure 17BAs shown, a substrate 301 is provided, and a second-type semiconductor heavily doped layer film 306, a second-type semiconductor doped layer film 307, an active layer film 308, and a first-type semiconductor doped layer film 302 are sequentially formed on the substrate 301.

[0143] For example, the first-type semiconductor doped layer film 302 is a p-type semiconductor doped layer film, the second-type semiconductor doped layer film 307 is an n-type semiconductor doped layer film, and the second-type 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.

[0144] For example, the active layer formed by the active layer film 308 can emit light and can serve as a light gain medium. The material of the active layer film 308 can refer to the related design in the above description, which will not be repeated here.

[0145] For example, as shown in Figure 17C For example, a resist is applied to the first-type semiconductor doped layer film 302 and is pre-cured to form a resist layer 303, i.e., a resist is applied to the n-type semiconductor doped layer film 302 and is pre-cured to form a resist layer 303. For example, the resist can be applied in a liquid state to the n-type semiconductor doped layer film 302, and then the liquid resist is pre-cured to be in a non-free-flowing state, i.e., a semi-solid state, so that the imprinting template 304 mentioned later can transfer its pattern to the resist layer 303. For example, the pre-curing method of the resist includes a method of irradiating ultraviolet light or a method of temperature curing.

[0146] For example, as shown in Figure 17D The resist layer 303 is nano-imprinted by using the imprinting template 304 to transfer the pattern of the imprinting template 304 to the resist layer 303, and is cured to form a resist layer pattern 305.

[0147] For example, the nano-imprinting technology includes ultraviolet nano-imprinting technology or thermal nano-imprinting technology.

[0148] For example, the curing method of the resist layer 303 includes a method of irradiating ultraviolet light or a method of temperature curing.

[0149] For example, in one example, the technique for nanoimprinting the resist layer 303 is ultraviolet nanoimprinting, and the method for curing the resist layer 303 is ultraviolet light irradiation; in another example, the technique for nanoimprinting the resist layer 303 is thermal nanoimprinting, and the method for curing the resist layer 303 is cooling curing.

[0150] For example, such as Figures 2-11 As shown, a patterning process is performed on a first type of semiconductor doped layer thin film 302 (p-type semiconductor doped layer thin film) using the resist layer pattern 305 as a mask to form a photonic crystal layer and a first dielectric layer thin film 309, and then the resist layer pattern 305 is removed. The first dielectric layer thin film 309 is located on the side of the photonic crystal layer closest to the substrate 301. The planar structure of the photonic crystal portion 100 included in the photonic crystal layer can be found in the above description. Figure 17D As shown, it will not be elaborated further here.

[0151] For example, photonic crystals fabricated using nanoimprint technology include holes of various shapes, hole arrays, nanogrooves of various shapes, and combinations of various nanostructures, which are not limited in the embodiments disclosed herein.

[0152] For example, during the process of forming a photonic crystal layer by patterning a p-type semiconductor doped layer thin film using the resist layer pattern 305 as a mask, a first dielectric layer thin film 309 is simultaneously formed on the side of the photonic crystal layer near the substrate 301, and the photonic crystal layer and the first dielectric layer thin film 309 are an integral structure. The first dielectric layer thin film 309 has a certain thickness and is also retained in the region corresponding to the via 101, that is, the first dielectric layer thin film 309 is a continuous single layer structure.

[0153] For example, such as Figure 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 any impact on the performance of the active layer film 308.

[0154] For example, the portion of the first type of semiconductor doped layer film 302 covered by the resist layer pattern 305 is the portion retained by the first type of semiconductor doped layer film, and the portion not covered is the portion etched away.

[0155] For example, such as Figure 17EAs 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 as the photonic crystal part 100 and are stacked, and the active layer film 308 is sandwiched between the photonic crystal part 100 and the second type of semiconductor doped layer film 307, 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.

[0156] For example, as shown in FIG. 3, a first type of semiconductor heavily doped layer film 310 (p-type semiconductor heavily doped layer film) is formed on the side of the photonic crystal layer away from the substrate 301. Figure 17F

[0157] 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, which can be formed by epitaxial growth or coating, and then the photoresist layer 312 is coated on the hard mask 311.

[0158] For example, as shown in FIG. 4, the photoresist layer 312 is patterned to form a photoresist pattern 313 covering a preset region, and the hard mask 311 is patterned with the photoresist pattern 313 as a mask and the photoresist pattern 313 is removed to form a hard mask pattern 314. Figure 17G

[0159] For example, the preset region is the mesa region of the photonic crystal filter, which can be defined by electron beam exposure and development, and then the part of the hard mask 311 except the mesa region is etched to form the hard mask pattern 314.

[0160] For example, as shown in FIG. 5, the hard mask pattern 314 is used as a mask to etch the second type of semiconductor doped layer film 307 and the active layer film 308 to form a photonic crystal filter 315. Figure 17G ​​As shown, a patterning process is performed using hard mask pattern 314 as a mask to form a first type of heavily doped semiconductor thin film 310 (second dielectric layer film), a photonic crystal layer, a first dielectric layer film 309, an active layer film 308, and a second type of semiconductor doped layer film 307 (n-type semiconductor doped layer film), respectively forming a second dielectric layer 107, a photonic crystal portion 100, a first dielectric layer 106, an active layer 105, and a second type of semiconductor doped layer 203 (n-type semiconductor doped layer 203). A gap exists between the edge of the orthogonal projection of the second type of semiconductor doped layer 203 (n-type semiconductor doped layer 203) onto the substrate 301 and the edge of the orthogonal projection of the second type of heavily doped semiconductor thin film 306 (n-type semiconductor doped layer film) onto the substrate 301. That is, the mesa of the photonic crystal filter is etched using hard mask pattern 314 as a mask until the second type of heavily doped semiconductor thin film 306 is exposed, and then the hard mask pattern 314 is removed.

[0161] For example, such as Figure 12 As shown, the first type of heavily doped semiconductor thin film 310 can serve as a second dielectric layer thin film, which can be etched to form a second dielectric layer 107, combined with... Figure 17H Each via 101 includes a first end 1011 and a second end 1012 along the extension direction of its channel. 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.

[0162] For example, such as Figures 17A-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 thin film 306 away from the substrate 301.

[0163] For example, the p-type electrode layer 316 can be formed by depositing p-type electrode material, and the n-type electrode layer 317 can be formed by depositing n-type electrode material. The embodiments disclosed herein are not limited in this respect, as long as the p-type electrode layer 316 and the n-type electrode layer 317 can be prepared.

[0164] For example, through Figure 12 The structure of the formed photonic crystal filter can be seen above. Figure 18 The relevant descriptions in the document will not be repeated here.

[0165] It should be noted that the photonic crystal part can also be formed in the first type of semiconductor heavily doped layer film 310, in which case the forming steps of the first type of semiconductor heavily doped layer film 310 and the first type of semiconductor doped layer film 302 are exchanged, and other process steps remain unchanged.

[0166] For example, Figure 18 A flowchart of another method for manufacturing a photonic crystal filter according to at least one embodiment of the present disclosure is shown in FIG. 6, which includes the following steps. Figures 19A-19I As shown in FIG. 6, the method includes the following steps.

[0167] S31: A substrate is provided, and a first type of semiconductor heavily doped layer film and a first type of semiconductor doped layer film are sequentially formed on the substrate.

[0168] S32: A resist is applied to the first type of semiconductor doped layer film, and a pre-curing process is performed to form a resist layer.

[0169] S33: A nanoimprint process is performed on the resist layer using an imprint template to transfer the pattern of the imprint template to the resist layer, and a curing process is performed to form a resist layer pattern.

[0170] S34: A patterning process is performed on the first type of semiconductor doped layer film using the resist layer pattern as a mask to form a photonic crystal layer, and the resist layer pattern is removed, the photonic crystal layer including a photonic crystal part, the photonic crystal part including a plurality of photonic crystal units arranged in an array, each photonic crystal unit including a plurality of through holes arranged in an array, each photonic crystal unit including a central region and a peripheral region surrounding the central region, the plurality of through holes including first through holes arranged in the central region and second through holes arranged in the peripheral region; the central region including Na x Na first through holes, where Na is a positive integer greater than or equal to 5; the number of second through holes on each side of the peripheral region is Na x Nb, where Nb is a positive integer greater than or equal to 1; the minimum distance between adjacent two first through holes is a first pitch Da, the minimum distance between adjacent two second through holes is a second pitch Db, and the minimum distance between the first through hole and the second through hole is a third pitch Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

[0171] S35: A first dielectric layer film is formed by epitaxial growth on the photonic crystal layer.

[0172] S36: A second type of semiconductor doped layer film, a second type of semiconductor heavily doped layer film, a hard mask, and a photoresist layer are sequentially formed on the side of the first dielectric layer film away from the substrate.

[0173] S37: performing patterning on the photoresist layer to form a photoresist pattern covering the preset region, performing patterning on the hard mask with the photoresist pattern as a mask and removing the photoresist pattern to form a hard mask pattern.

[0174] S38: performing patterning on the second-type semiconductor heavily doped layer film, the second-type semiconductor doped layer film, the active layer film, the first dielectric layer film and the photonic crystal layer with the hard mask pattern as a mask to form a second-type semiconductor heavily doped layer, a second-type semiconductor doped layer, an active layer, a first dielectric layer and a photonic crystal part respectively, and there is a gap between the edge of the orthographic projection of the photonic crystal part on the substrate and the edge of the orthographic projection of the first-type semiconductor heavily doped layer film on the substrate.

[0175] S39: removing the hard mask pattern, forming a p-type electrode layer on the side of the second-type semiconductor heavily doped layer away from the substrate, and forming an n-type electrode layer on the side of the first-type semiconductor heavily doped layer film away from the substrate in the gap.

[0176] For example, Figure 19A A process diagram of a preparation method of a photonic crystal filter is provided for at least one embodiment of the present disclosure.

[0177] For example, as Figure 19B shown, a substrate 301 is provided, and a first-type semiconductor heavily doped layer film 310 and a first-type semiconductor doped layer film 302 are sequentially formed on the substrate 301.

[0178] For example, the first-type semiconductor doped layer film 302 is an n-type semiconductor doped layer film, and the first-type 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 semiconductor doped layer film mentioned later is a p-type semiconductor doped layer.

[0179] For example, as Figure 19CAs shown, a resist is applied to the first type of semiconductor doped layer film 302 and pre-cured to form a resist layer 303. For example, a liquid resist can be applied to the n-type semiconductor doped layer film 302 and pre-cured to a non-free flowing state, i.e. a semi-solid state, such that the imprint template 304 can transfer its pattern to the resist layer 303. For example, the pre-curing process can include a UV irradiation process or a temperature reduction process.

[0180] For example, as shown in FIG. 3B, the resist layer 303 is nano-imprinted using the imprint template 304 to transfer the pattern of the imprint template 304 to the resist layer 303 and cured to form a resist layer pattern 305. Figure 19D

[0181] For example, the nano-imprinting technique can include a UV nano-imprinting technique or a thermal nano-imprinting technique.

[0182] For example, the curing process of the resist layer 303 can include a UV irradiation process or a temperature reduction process.

[0183] For example, in one example, the nano-imprinting technique of the resist layer 303 is a UV nano-imprinting technique and the curing process of the resist layer 303 is a UV irradiation process; in another example, the nano-imprinting technique of the resist layer 303 is a thermal nano-imprinting technique and the curing process of the resist layer 303 is a temperature reduction process.

[0184] For example, as shown in FIG. 3C, the resist layer pattern 305 is used as a mask to etch the n-type semiconductor doped layer film 302 to form a patterned n-type semiconductor doped layer film 306. Figure 19E ​As shown, a patterning process is performed on a first type of semiconductor doped layer thin film 302 (n-type semiconductor doped layer thin film) using the resist layer pattern 305 as a mask to form a photonic crystal layer, and then the resist layer pattern 305 is removed. The photonic crystal layer includes multiple vias arranged in an array. The photonic crystal layer includes a photonic crystal section, which in turn includes multiple photonic crystal units arranged in an array. Each photonic crystal unit includes multiple vias arranged in an array. Each photonic crystal unit includes a central region and a peripheral region surrounding the central region. The multiple vias include first vias arranged in an array in the central region and second vias arranged in an array in the peripheral region. The central region includes Na×Na first vias, where Na is a positive integer greater than or equal to 5. The number of second vias on each side of the peripheral region is Na×Nb, where Nb is a positive integer greater than or equal to 1. The minimum distance between two adjacent first vias is a first spacing Da, the minimum distance between two adjacent second vias is a second spacing Db, and the minimum distance between a first via and a second via is a third spacing Dg, satisfying Na*Da+Nb*Db+Dg≤10μm.

[0185] For example, the portion of the first type of semiconductor doped layer film 302 covered by the resist layer pattern 305 is the portion retained by the first type of semiconductor doped layer film, and the portion not covered is the portion etched away.

[0186] For example, photonic crystals fabricated using nanoimprint technology include holes of various shapes, hole arrays, nanogrooves of various shapes, and combinations of various nanostructures, which are not limited in the embodiments disclosed herein.

[0187] For example, such as Figure 19F As shown, a first dielectric layer thin film 309 is epitaxially grown on the photonic crystal layer.

[0188] For example, the first dielectric layer thin film 309 is on the side of the photonic crystal layer away from the substrate 301.

[0189] For example, such as Figure 19G 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.

[0190] For example, the second type of semiconductor doped layer thin film 307 can be formed on the surface of the first dielectric layer thin film 309 by epitaxial growth. The hard mask 311 is made of silicon dioxide and can be formed by epitaxial growth or coating, and then a photoresist layer 312 is coated on the hard mask 311.

[0191] For example, as shown in Figure 19H The photoresist layer 312 is patterned to form a photoresist pattern 313 covering the preset region, the hard mask 311 is patterned with the photoresist pattern 313 as a mask and the photoresist pattern 313 is removed, to form a hard mask pattern 314.

[0192] For example, the preset region is the mesa region of the photonic crystal filter, the mesa region of the photonic crystal filter can be defined by electron beam exposure and development, and then the part of the hard mask 311 except the mesa region is etched to form the hard mask pattern 314.

[0193] For example, as shown in Figure 19H The second type of semiconductor heavily doped layer film 306, the second type of semiconductor doped layer film 307, the active layer film 308, the first dielectric layer film 309 and the photonic crystal layer are patterned with the hard mask pattern 314 as a mask to form a second type of semiconductor heavily doped layer (p-type semiconductor heavily doped layer 205), a second type of semiconductor doped layer (p-type semiconductor doped layer 204), an active layer 105, a first dielectric layer 106 and a photonic crystal part 100, respectively, and there is a gap between the edge of the orthographic projection of the photonic crystal part 100 on the substrate 301 and the edge of the orthographic projection of the first type of semiconductor heavily doped layer film 310 (n-type semiconductor heavily doped layer film) on the substrate 301. That is, the mesa of the photonic crystal filter is etched with the hard mask pattern 314 as a mask until the first type of semiconductor heavily doped layer film 310 is exposed, and then the hard mask pattern 314 is removed.

[0194] For example, as shown in Figure 19H The active layer 105 can emit light and can act as a light gain medium, and the material of the active layer film 105 can refer to the related design described above, which will not be repeated here.

[0195] For example, as shown in Figure 13 The first type of semiconductor heavily doped layer film 310 can act as a second dielectric layer film, which is a second dielectric layer, in combination with Figure 19I Each via hole 101 includes opposite first and second ends 1011 and 1012 along the extension direction of its channel, the first end 1011 is connected with the first dielectric layer film 309 (the first dielectric layer is formed later), and the second end 1012 is connected with the second dielectric layer film 310 (the first dielectric layer is formed later).

[0196] For example, as shown in Figures 19A-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 on the side of the first type of semiconductor heavily doped layer film 310 away from the substrate 301 in the gap.

[0197] 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, and embodiments of the present disclosure are not limited in this regard as long as the p-type electrode layer 316 and the n-type electrode layer 317 can be prepared.

[0198] 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, and embodiments of the present disclosure are not limited in this regard as long as the p-type electrode layer 316 and the n-type electrode layer 317 can be prepared. Figure 13 The structure of the photonic crystal filter formed can refer to the related description in the above Figure 20 , and will not be described here again.

[0199] It should be noted that the photonic crystal part can also be formed in the first type of semiconductor heavily doped layer film 310, at which time the forming 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 other process steps remain unchanged.

[0200] For example, Figure 20 A block diagram of a spectrum detection system provided by at least one embodiment of the present disclosure is shown in FIG. 4, which includes a semi-transmissive and semi-reflective 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. Figure 11

[0201] For example, the pattern of the structure to be detected can be detected by the light path based on the 4f optical system 404, so that the rich pattern generated under the volume of the extremely small array unit represents the high-Q resonance peak corresponding to different characteristic wavelengths generated by the structure to be detected. The spectrum detection method using the spectrum detection system can be excited out of the plane, so that coupling and modulation are not required, and the structure of the spectrum detection system is simple, and higher spectrum detection accuracy can be achieved by simple array of the photonic crystal part, and the spectrum detection accuracy is adjustable. In addition, the size of the spectrum detection system is smaller, so as to facilitate further miniaturization of the spectrum detection instrument.

[0202] ​For example, the 4f optical system refers to when two coherent polarized lights are input, special optical devices such as a cosine grating, an exchange plane, etc. are used to make the input light produce a diffraction spectrum on a screen. Precise transverse movement of the cosine grating can continuously change the phase difference of the diffraction order of the two lights, so as to achieve the purpose of subtraction or addition of the diffraction intensity, that is, there are two lenses with a focal length of f, a distance of 2f, an object distance of f, and a distance of f. Therefore, it is a 4f optical system, and only an optical system with a distance greater than 4f can be used as a zoom system.

[0203] For example, in combination with the planar structure of the photonic crystal filter in Figure 21 , based on the 600nm SOI process platform and the measurement system integrated with the 4f optical system and the polarization filtering method, the SOI pattern is first corrected by the Beamer software (PEC), the field size is selected to be 500 microns*500 microns, and the sub-field size is selected to be 10 microns*10 microns. The field correction is realized through the Beamer software. Through electron beam exposure (EBL) and inductively coupled plasma etching (ICP), a photonic crystal microcavity pattern with a size of about 10 microns*10 microns is formed.

[0204] For example, the upper computer controls the multi-spectral light source, presents a pattern with appropriate size on the imaging structure 403 through the 4f optical system, and records the presented pattern and the PD response through the upper computer at the same time, wherein the magnification of the 4f optical system 404 is 0.5.

[0205] The embodiment of the present disclosure solves the photonic crystal filter-based spectrum detection system and spectrum detection method. The photonic crystal part included in the spectrum detection system has regular shape units, each regular shape unit has multiple frequency selection capabilities at different wavelengths, the frequency selection capability can be adjusted according to the required spectrum recovery accuracy, and the wavelengths corresponding to the characteristic frequencies of adjacent units in the array unit are irrelevant, thereby effectively avoiding the coupling between adjacent units in the array unit due to similar wavelengths.

[0206] For example, the spectrum detection method includes forming a characteristic different to-be-detected spectrum, inputting the to-be-detected spectrum into the spectrum detection system in any one of the above, and distinguishing the to-be-detected spectrum with different characteristics. The spectrum detection method includes the following steps.

[0207] First, the light source is irradiated, and a host computer forms a characteristic different spectrum to be measured. After using a polarization filtering method and passing through a half-transmission half-reflection mirror, part of the light passes through an objective lens and is irradiated onto a photonic crystal filter. The reflected light passing through the photonic crystal filter passes through the objective lens again and reaches the half-transmission half-reflection mirror, so that the part of the light enters a 4f optical system. The 4f optical system is designed to have a magnification matching the field of view and the imaging structure, and a near-field pattern generated by the light passing through the photonic crystal filter is presented on the imaging structure.

[0208] Second, the host computer controls the waveform shaper to modulate the wide-spectrum light source, records the patterns of the imaging structure under different spectra obtained by measuring the test light path, combines the filtering characteristics of the photonic crystal filter, processes and analyzes the recorded data by using a neural network, and obtains the spectral information of the light source to be measured.

[0209] Third, a large number of input unknown spectra and corresponding near-field patterns of the test are recorded as inputs of the neural network for training. A pre-trained EfficientNet-B0 model is used, and a self-defined loss function combining cosine similarity loss and mean square error loss is used. A specific learning rate adjustment mechanism and regularization are combined to prevent overfitting during training, so as to improve the training effect of the model. The whole process includes data preparation, model training, verification and testing, and the loss curve in the training process is visualized.

[0210] For example, the photonic crystal filter applied to the spectrum detection system according to the embodiments of the present disclosure can obtain the following technical effects: the photonic crystal filter generates rich high-Q resonances and corresponding rich near-field pattern characteristics, has excellent frequency selection characteristics in a very small volume, and can be coupled out of the plane to adapt to more application scenarios. In addition, the spectrum detection can be realized without calibration through the training mode of the neural network, and the method has good robustness to process errors in processing, thereby facilitating large-scale industrial production.

[0211] For example, Figure 21 The pattern of the photonic crystal microcavity array measured by the spectrum test system with the photonic crystal filter provided by at least one embodiment of the present disclosure can be used for Figure 22In the spectral test process shown, the input light has a wavelength of 1550 nm and a line width of 10 pm. After considering the inherent CMOS noise and environmental background noise, 40% of the collected images are added with 2% Gaussian noise. These processed images are 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 1280x1024x1. The image is sampled through an initial 3x3 convolutional layer to extract initial features. The subsequent network uses MBConv modules to optimize computational efficiency, gradually adjusts the number of channels and reduces the spatial resolution, and finally generates 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 batch normalization and dropout (dropout rate of 30%) are applied after each convolutional neural network and fully connected layer for regularization to prevent overfitting. During the training process, the AdamW optimizer is used with an initial learning rate of 0.0001, and learning rate decay is applied when the performance on the validation set tends to be stable. The loss function is a combination of MSE and cosine similarity, which is evaluated between the network output and the standard spectrum. The model is trained for 90 epochs, the performance is monitored using the validation set, and the final evaluation is performed on the test set, and the model weights and prediction results are saved. The entire process includes data preparation, model training, validation, and testing, and the loss curve during training is visualized.

[0212] For example, Figure 22 The loss curve of the demodulation spectral neural network training process provided by at least one embodiment of the present disclosure is shown in FIG. 6, from which it can be seen that the loss value obtained by training is in the order of 10 Figure 23 -3 The fitting goodness of the spectrum is greater than 97%, and the difference is caused by non-ideality due to process errors, sensitivity of the imaging structure, noise, etc.

[0213] For example, Figure 23 The spectral performance characterization diagram provided by at least one embodiment of the present disclosure is shown in FIG. 7, from which it can be seen that when the input spectrum is a multi-peak spectral type, the spectral demodulation capability of the spectral detection system and the test results provided by the embodiment of the present disclosure exhibit a spectral demodulation capability of 0.25 nm resolution under a bandwidth of 80 nm. Figure 24 The spectral 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.

[0214]

[0215] ​​For example, in the microcavity sensor, the photonic crystal filter provided by the embodiment 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, so that the influence of environmental factors such as temperature and humidity on the microcavity sensor can be measured by measuring the change of the pattern of the two-dimensional photonic crystal microcavity array, so as to prepare a sensor with high sensitivity.

[0216] For example, in the spectral imager, the photonic crystal filter provided by the embodiment of the present disclosure has the characteristics of miniaturization and wide spectral detection range, that is, by being densely packed, it can be used as a spectral imager with imaging and high wavelength resolution, so that a spectral imager with spatial data can be prepared by measuring the imaging algorithm of the multiple array patterns after dense packing.

[0217] For example, Figure 24 The simulation performance graph of the spectral detection system provided by at least one embodiment of the present disclosure avoids the field stitching problem, as shown in ​ When there are problems such as field stitching, mechanical movement, field distortion, and edge effect in electron beam exposure, the performance graph of the simulation (Na=7, Nb=8) for structure units greater than and less than 10 microns*10 microns is compared by simulation. When there is a 80nm offset in the x direction or y direction beyond the 10 microns*10 microns field range, the microcavity Q value will decrease from 22x10 4 to 8x10 4 However, the structure (Na=6, Nb=7) in the embodiment of the present disclosure does not have such an impact when the field offset occurs, and can maintain the Q value at 16x10 4 The array unit less than 10 microns*10 microns proposed by the embodiment of the present disclosure can effectively avoid the above problems, so that the spectral detection system has high robustness.

[0218] The spectral detection system and spectral detection method provided by the embodiment of the present disclosure can detect the pattern of the structure to be detected based on the optical path of the 4f optical system, and in addition, a large number of patterns can be generated under a very small array unit volume, which represents the high-Q resonance peaks of different characteristic wavelengths generated by the structure to be detected, thereby realizing detection of the to-be-detected spectrum.

[0219] The following points need to be explained:

[0220] (1) The drawings of the embodiments of the present disclosure only involve the structures involved in the embodiments of the present disclosure, and other structures can be referred to the usual design.

[0221] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of the layer or region is enlarged or reduced, that is, the drawings are not drawn according to the actual proportion.

[0222] (3) In the case of no conflict, the embodiments of the disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0223] The above is only a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and the protection scope of the disclosure should be subject to the protection scope of the claims.

Claims

1. A photonic crystal optical filter, characterized by, The photonic crystal filter comprises: a photonic crystal part, wherein the photonic crystal part comprises a plurality of photonic crystal units arranged in an array, each of the photonic crystal units comprises 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, the plurality of through holes comprises first through holes arranged in the central region and second through holes arranged in the peripheral region; the central region 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 region 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 pitch Da, the minimum distance between two adjacent second through holes is a second pitch Db, and the minimum distance between the first through hole and the second through hole is a third pitch Dg, and Na*Da+Nb*Db+Dg≤10μm is satisfied.

2. The photonic crystal optical filter of claim 1, wherein, the minimum distance between two adjacent photonic crystal units is a fourth pitch Nag, and the fourth pitch Nag is greater than or equal to 5 microns and less than or equal to 10 microns.

3. The photonic crystal optical filter of claim 1, wherein, a transition region is further included between the central region and the peripheral region, the through holes further comprise third through holes arranged in the transition region, the arrangement density of the first through holes is greater than that of the third through holes, and the arrangement density of the third through holes is greater than that of the second through holes, the first pitch is less than the fifth pitch, and the fifth pitch is less than the second pitch; or, the arrangement density of the first through holes is less than that of the third through holes, and the arrangement density of the third through holes is less than that of the second through holes, the first pitch is greater than the fifth pitch, and the fifth pitch is greater than the second pitch.

4. The photonic crystal optical filter of claim 3, wherein, The planar shapes of the first through holes, the second through holes and the third through holes are the same, the planar size of the first through holes is smaller than that of the second through holes, and the planar size of the second through holes is smaller than that of the third through holes.

5. The photonic crystal optical filter of claim 1, wherein, The first through holes are arranged in a matrix, the overall outer contour shape of the first through holes arranged in a matrix is a quadrilateral, the second through holes are arranged on the side away from the center of the central region of each side of the quadrilateral, and the second through holes surround the overall first through holes arranged in a 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 region is a square; the peripheral region comprises four edge regions and four corner regions, and the shapes of the four edge regions and the four corner regions are both rectangles; the long sides of each of the four edge regions close to the central region are respectively aligned with the four sides of the central region and have equal lengths. The four corner regions are located in directions away from the center of the square at four corners of the center region, and adjacent two sides of each of the four corner regions are arranged in alignment with two short sides of the two side regions adjacent thereto and have equal length.

7. The photonic crystal optical filter of claim 6, wherein, The four side regions are rectangular regions formed by Na×Nb second through holes, and the four corner regions are square regions formed by Nb×Nb second through holes, where Na and Nb are positive integers.

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

9. The photonic crystal optical filter of claim 8, wherein, Further comprising a second dielectric layer disposed on a side of the photonic crystal part away from the first dielectric layer, wherein each of the through holes comprises opposite first and second ends along the extension direction of the channel thereof, the first end is connected with the first dielectric layer, and the second end is connected with the second dielectric layer.

10. The photonic crystal optical filter of claim 9, wherein, Further comprising: an n-type substrate; an n-type semiconductor heavily doped layer and an n-type semiconductor doped layer disposed on the n-type substrate in sequence; a p-type semiconductor doped layer and a p-type semiconductor heavily doped layer disposed on a side of the active layer away from the n-type substrate in sequence; 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 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 disposed 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; the p-type semiconductor doped layer is configured as the photonic crystal part and the first dielectric layer. Further comprising:

11. The photonic crystal optical filter of claim 9, wherein, an n-type substrate; an n-type semiconductor heavily doped layer and an n-type semiconductor doped layer disposed on the n-type substrate in sequence; a p-type semiconductor doped layer and a p-type semiconductor heavily doped layer disposed on a side of the active layer away from the n-type substrate in sequence; 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 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 disposed 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; the n-type semiconductor doped layer is configured as the photonic crystal part and the first dielectric layer. It comprises a half-transmission half-reflection mirror, an objective lens, an imaging structure, a 4f optical system, and the photonic crystal filter of any one of claims 1-11.

12. A spectroscopic detection system, characterized by ​ ​

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