A two-dimensional photonic crystal microcavity

Abstract

The present invention provides a two-dimensional photonic crystal microcavity, comprising: a first dielectric layer, a second dielectric layer, and a photonic crystal layer disposed between the first and second dielectric layers; the photonic crystal layer is provided with periodically arranged cylindrical through-holes, the cylindrical through-holes being perpendicular to the first and second dielectric layers; the photonic crystal layer comprises a central region and a peripheral region; the central region comprises Na×Na cylindrical through-holes, where Na is a positive integer greater than or equal to 1; the peripheral region surrounds the central region and is used to suppress energy leakage from the two-dimensional photonic crystal microcavity from the peripheral region or to control energy radiation from the two-dimensional photonic crystal microcavity to the peripheral region. The photonic crystal microcavity of the present invention has a high quality factor and excellent optical performance, and its very small size facilitates integration into optical devices. Furthermore, it is robust to process errors during manufacturing, facilitating large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the field of microwaves and light waves, and in particular to a two-dimensional photonic crystal microcavity which can be applied to devices such as microcavity lasers, microcavity sensors, microcavity filters, and microcavity detectors. Background Art

[0002] A photonic crystal microcavity is an optical device that can confine light in a limited space. Due to its small size, high quality factor, large-scale integration, and suitability for single-mode operation at various wavelengths, photonic crystal microcavities have numerous applications in physics research and engineering, including microfilters, low-threshold lasers, photonic chips, nonlinear optics, and quantum information processing. The quality factor (Q) and mode volume (V) are two important indicators for evaluating photonic crystal microcavities and are key factors in their performance in applications. Therefore, improving the quality factor and reducing the mode volume of photonic crystal microcavities have become major research areas.

[0003] Early researchers proposed a photonic crystal microcavity based on defect modes and a two-dimensional photonic bandgap defect-mode laser. The principle is to remove one or more structures in the photonic crystal to create a local defect. Then, by precisely changing the geometry of the photonic crystal near the defect to match the microcavity mode, energy leakage is suppressed.

[0004] However, the aforementioned structures place extremely high demands on the process precision of microcavity fabrication to achieve a sufficiently good quality factor, which restricts their large-scale application. Therefore, how to design the simplest microcavity structure while minimizing the requirements for process error while improving the optical performance of the microcavity has become a challenging problem. Summary of the Invention

[0005] In order to solve the problems of radiation suppression on the upper and lower surfaces and energy leakage on the side edges of a two-dimensional photonic crystal microcavity, the present application provides a two-dimensional photonic crystal microcavity, comprising:

[0006] a first dielectric layer, a second dielectric layer, and a photonic crystal layer disposed between the first dielectric layer and the second dielectric layer;

[0007] The photonic crystal layer is provided with periodically arranged cylindrical through holes, and the cylindrical through holes are perpendicular to the first dielectric layer and the second dielectric layer;

[0008] The photonic crystal layer includes a central area and a peripheral area; the central area includes Na×Na cylindrical through holes, where Na is a positive integer greater than or equal to 1; the peripheral area wraps the central area, and is used to suppress the energy in the two-dimensional photonic crystal microcavity from leaking from the peripheral area or controlling the energy in the two-dimensional photonic crystal microcavity to radiate toward the peripheral area.

[0009] In one embodiment, the cylindrical through hole may be filled with gas, solid or liquid material.

[0010] In one embodiment, the filling rate and filling shape of the filling material in the cylindrical through hole are adjustable.

[0011] In one embodiment, the radius of the cylindrical through holes in the peripheral area, the number of the cylindrical through holes, and the distance between adjacent cylindrical through holes are all adjustable.

[0012] In one embodiment, the size and central wavelength of the two-dimensional photonic crystal microcavity can be adjusted by changing at least one of the size of Na, the distance between adjacent cylindrical through holes in the central region, the radius of the cylindrical through holes in the central region, the thickness of the photonic crystal layer, the refractive index of the filling material in the cylindrical through holes in the central region, and the refractive index of the photonic crystal.

[0013] In one embodiment, the radiation energy at the contact surface between the photonic crystal layer and the first dielectric layer and the second dielectric layer can be adjusted by changing the ratio of the thickness of the photonic crystal layer material to the distance between adjacent cylindrical through holes in the central area and / or the radius of the cylindrical through holes.

[0014] In one embodiment, the bandgap of the central wavelength of the two-dimensional photonic crystal microcavity can be formed by changing at least one of the distance between adjacent cylindrical through holes in the peripheral region, the radius of the cylindrical through holes in the peripheral region, and the spacing between the peripheral region and the central region.

[0015] In one embodiment, the radiation in any direction on the side of the peripheral region of the two-dimensional photonic crystal microcavity can be adjusted by individually changing the radius of the cylindrical through holes and / or the distance between the cylindrical through holes in the peripheral region corresponding to the direction.

[0016] In one embodiment, the radiation in any side direction of the two-dimensional photonic crystal microcavity can be adjusted by removing individually or partially removing the cylindrical through holes in the peripheral region corresponding to the side direction.

[0017] In one embodiment, the array formed by the cylindrical through holes is a square array, and the central area is located in the middle of the array;

[0018] The peripheral area includes four side areas and four corner areas, and the side areas and the corner areas are all rectangular;

[0019] One of the long sides of the four side areas is equal in length to the four sides of the central area and they are aligned;

[0020] The four corner regions are respectively located at the four corners of the square array, and two sides of the four corner regions are respectively equal to one short side of two adjacent side regions and are aligned.

[0021] In one embodiment, the four side regions are all rectangular regions formed by an arrangement of Na×Nb cylindrical through holes, where Nb is a positive integer greater than or equal to 1.

[0022] In one embodiment, the four corner regions are all square regions formed by an arrangement of Nb×Nb cylindrical through holes, where Nb is a positive integer greater than or equal to 1.

[0023] The present application also provides a microcavity laser, comprising the two-dimensional photonic crystal microcavity in any of the above embodiments, wherein the first dielectric layer and / or the second dielectric layer in the two-dimensional photonic crystal microcavity is a medium having optical gain at the central wavelength of the microcavity.

[0024] The present application also provides a microcavity detector, comprising the two-dimensional photonic crystal microcavity in any one of the above embodiments, wherein the first medium layer is an air layer, and a photosensitive area is provided between the second medium layer and the photonic crystal layer.

[0025] The present invention solves the two problems of radiation suppression from the top and bottom surfaces of a two-dimensional photonic crystal microcavity and energy leakage from the sides. The radiation from the top and bottom surfaces is suppressed by destructive interference of radiation waves in the vertical direction, while energy leakage is suppressed in the horizontal direction by designing heterostructure boundaries. This confines the energy within the photonic crystal microcavity structure, improving the quality factor (Q) of the photonic crystal microcavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the side structure of the two-dimensional photonic crystal microcavity of the present invention;

[0028] Figure 2A A cross-sectional view of a cylindrical through-hole filled in a photonic crystal layer according to the present invention;

[0029] Figure 2B A cross-sectional view of another cylindrical through-hole filling in a photonic crystal layer according to the present invention;

[0030] Figure 2C A cross-sectional view of another cylindrical through-hole filling in a photonic crystal layer according to the present invention;

[0031] Figure 3 is a schematic diagram of the top surface of the photonic crystal layer of the present invention;

[0032] Figure 4 is a partially enlarged view of the schematic top surface of the photonic crystal layer of the present invention;

[0033] Figure 5 This is the relationship between the energy radiation intensity and wavelength of the photonic crystal microcavity measured by the polarization filtering method;

[0034] Figure 6 The statistical histogram of the quality factor of the photonic crystal microcavity shown in the present invention;

[0035] Figure 7 A three-dimensional schematic diagram of a photonic crystal microcavity laser shown in the present invention;

[0036] Figure 8 This is a three-dimensional schematic diagram of a photonic crystal microcavity detector shown in the present invention.

[0037] Figure Number:

[0038] 1-first dielectric layer; 2-photonic crystal layer; 21-central region; 22-peripheral region; 23-peripheral region; 3-cylindrical through hole; 4-second dielectric layer; 5-first contact surface; 6-second contact surface; 7-filling medium; 8-filling medium; 9-filling medium; 10-photosensitive region. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] See also Figures 1 to 3 , this application provides a two-dimensional photonic crystal microcavity, Figure 1 is a schematic diagram of the side structure of a two-dimensional photonic crystal microcavity, as shown in Figure 1 As shown, the two-dimensional photonic crystal microcavity includes:

[0041] A first dielectric layer 1 with a refractive index of n1, a photonic crystal layer (PhC layer) 2 with a refractive index of n2, and a second dielectric layer 4 with a refractive index of n3; the photonic crystal layer 2 is arranged between the first dielectric layer 1 and the second dielectric layer 4, and has a thickness of h.

[0042] Periodically arranged cylindrical through holes 3 are provided in the photonic crystal layer 2 , and the cylindrical through holes 3 are perpendicular to the first dielectric layer 1 and the second dielectric layer 4 .

[0043] The cylindrical through hole 3 is filled with a medium with a refractive index of n0, which can be a gas (such as air), a solid or a liquid material. It is understandable that the medium filled in the cylindrical through hole 3 can also be the same medium as the material of the photonic crystal layer 2.

[0044] The relationship among the refractive index n0, the refractive index n1, and the refractive index n3 is not limited here. In practical applications, they can be set to the same refractive index or different refractive indices as needed.

[0045] At the same time, the medium filling rate and filling shape in the cylindrical through hole 3 can also be adjusted as needed, such as Figures 2A to 2C As shown, the lower half of the cylindrical through hole 3 or one side of the cylindrical through hole 3 can be filled, or any other filling method can be used.

[0046] The materials of the first dielectric layer 1 , the photonic crystal layer 2 , the second dielectric layer 4 and the material filled in the cylindrical through hole 3 may be materials with or without gain to the central wavelength of the two-dimensional photonic crystal microcavity.

[0047] Figure 3 is the top view of the photonic crystal layer 2 of the two-dimensional photonic crystal microcavity. Figure 3 As shown, the photonic crystal layer is divided into a central region 21 and a peripheral region surrounding the central region 21. The peripheral region includes four side regions 22 and four corner regions 23. The central region 21 includes Na×Na cylindrical through holes, where Na is a positive integer greater than or equal to 1. The radius of the cylindrical through holes 3 in the central region 21, the distance between two adjacent cylindrical through holes, and the value of Na can all be changed.

[0048] Cylindrical through holes 3 are also provided in the edge region 22 and the corner region 23, and the radius, number and distance between adjacent cylindrical through holes 3 in the edge region 22 and the corner region 23 can be adjusted. By adjusting the above-mentioned features in the edge region 22 and the corner region 23, it is possible to suppress the energy in the two-dimensional photonic crystal microcavity from leaking from the edge region 22 and the corner region 23 or control the energy in the two-dimensional photonic crystal microcavity to radiate to the edge region 22 and the corner region 23.

[0049] The following further illustrates how to adjust the parameters of a two-dimensional photonic crystal microcavity to control the energy radiation of the two-dimensional photonic crystal microcavity through examples.

[0050] In one embodiment, the size and central wavelength of the two-dimensional photonic crystal microcavity can be changed by adjusting at least one of the size of Na, the distance between adjacent cylindrical through holes in the central region 21, the radius of the cylindrical through hole 3 in the central region 21, the thickness h of the photonic crystal layer 2, the refractive index n0 of the material filled in the cylindrical through hole in the central region 21, and the refractive index n2 of the photonic crystal layer 2.

[0051] The contact surface between the photonic crystal layer 2 and the first dielectric layer 1 is 5, and the contact surface between the photonic crystal layer 2 and the second dielectric layer 4 is 6. In one embodiment, by adjusting the ratio of the thickness h of the photonic crystal layer 2 to the distance between adjacent cylindrical through holes in the central region 21 and / or the radius of the cylindrical through holes, the energy radiation intensity between the contact surface 5 of the photonic crystal layer 2 and the first dielectric layer 1 and the contact surface 6 of the photonic crystal layer 2 and the second dielectric layer 4 can be adjusted, thereby achieving regulation of the radiation energy on the upper and lower surfaces of the photonic crystal layer.

[0052] In one embodiment, by adjusting at least one of the distance between adjacent cylindrical through holes in the side region 22 and the corner region 23, the radius of the cylindrical through holes in the peripheral region 22, and the spacing between the side region 22 and the corner region 23 and the central region 21, a bandgap of the central wavelength of the two-dimensional photonic crystal microcavity can be formed, thereby confining energy in the central region 21 and suppressing side energy leakage of the microcavity.

[0053] In one embodiment, by separately adjusting the radius of the cylindrical through holes 3 in the side region 22 and the corner region 23 corresponding to any direction of the side and / or the distance between adjacent cylindrical through holes, the energy leakage of the two-dimensional photonic crystal microcavity in that direction can be controlled, thereby achieving the radiation of the energy in the two-dimensional photonic crystal microcavity to any direction of the side.

[0054] In one embodiment, by separately adjusting the number of cylindrical through holes in the side region 22 and the corner region 23 corresponding to any direction of the side, such as removing some or all of the cylindrical through holes, the energy leakage of the two-dimensional photonic crystal microcavity in that direction can be controlled, thereby achieving the radiation of the energy in the two-dimensional photonic crystal microcavity to any direction of the side.

[0055] It can be understood that the above embodiments can be implemented individually or two or more can be implemented simultaneously.

[0056] As can be seen from the above embodiments, the present application can suppress energy radiation from above and below the photonic crystal layer, as well as energy leakage from the sides, confining the energy within the two-dimensional photonic crystal microcavity and improving the quality factor Q of the microcavity. Furthermore, by destroying some of the energy suppression conditions of the two-dimensional photonic crystal microcavity, energy can be controlled to radiate in any direction, achieving energy coupling between the energy in the microcavity and the optical structure outside the microcavity.

[0057] In one embodiment, if Figure 3 and Figure 4 As shown, the array formed by the cylindrical through holes is a square array, wherein the central area 21 is located in the center of the square array; a long side of each side area 22 is equal to a side length of the central area 21 and is arranged in alignment; the four corner areas are respectively located at the four corners of the square array, and the adjacent two sides of each corner area 23 are equal to a short side of the two adjacent side areas and are arranged in alignment.

[0058] The radius of the cylindrical through-hole in the central region 21 is ra, and the distance between adjacent cylindrical through-holes is a.

[0059] Each of the four side regions 22 includes Na×Nb cylindrical through holes with a radius of rb, where Nb is a positive integer greater than or equal to 1; in the Na direction, that is, in the direction in which Na cylindrical through holes are provided in the four side regions 22, the distance between adjacent cylindrical through holes is a; in the Nb direction, that is, in the direction in which Nb cylindrical through holes are provided in the four side regions 22, the distance between adjacent cylindrical through holes is b.

[0060] Each of the four corner regions 23 includes Nb×Nb cylindrical through holes, the radius of the cylindrical through holes is rb, and the distance between adjacent cylindrical through holes is b.

[0061] The intervals between the central region 21 , the side regions 22 and the corner regions 23 are all g.

[0062] The following is a specific example based on a 600nm SOI process platform to further illustrate the above embodiment.

[0063] Combine Figure 1 As shown, in this example, the first dielectric layer 1, the second dielectric layer 4, and the material filling the cylindrical through hole are all air dielectrics with a refractive index of 1, that is, n0 = n1 = n3 = 1; the photonic crystal layer 2 is a silicon dielectric with a thickness of h = 600 nm and a refractive index n2 = 3.48. The second dielectric layer 4 below the photonic crystal layer 2, i.e., the air layer, is formed by etching a silicon dioxide layer.

[0064] See also Figures 3 and 4 Schematic diagram of the photonic crystal layer structure. The cylindrical through-hole radius ra in the central region 21 is 175 nm, the distance between adjacent cylindrical through-holes is a = 529 nm, and Na = 17. The cylindrical through-hole radius rb in the side region 23 is 175 nm, Nb = 10, and the distance between adjacent cylindrical through-holes in the Nb direction is b = 552 nm. Correspondingly, the parameters in the corner region 24 are set to Nb = 10, the cylindrical through-hole radius rb = 175 nm, and the distance between adjacent cylindrical through-holes is b = 552 nm. The spacing g between the central region 21, side region 23, and corner region 24 is 541 nm.

[0065] The pattern processing of SOI is achieved through electron beam lithography (EBL) and inductively coupled plasma etching (ICP), and the size of the two-dimensional photonic crystal microcavity pattern is about 19.8um×19.8um.

[0066] Figure 5 This is the relationship between the energy radiation intensity and wavelength of the two-dimensional photonic crystal microcavity measured in the experiment, where the quality factor Q is 1.09×10 6The quality factor of the two-dimensional photonic crystal microcavity structure in this example is calculated by the finite element simulation software COMSOL to be 8.19×10 6 The difference between the actual test results and the simulation results comes from the non-ideality caused by process errors.

[0067] Figure 6 The figure is a statistical histogram of the quality factor of 87 samples of the two-dimensional photonic crystal microcavity structure designed according to the parameters of this example. The average value of these 87 samples is 6.65×10 5 , with a standard deviation of 1.22×10 5 .

[0068] When a is adjusted to 518 nm, the energy radiation above and below the photonic crystal layer increases, and the quality factor Q of the microcavity decreases to 1.24×10 5 According to the experimental data, by changing the distance a between adjacent cylinders in the central region 21, the energy radiation intensity above and below the photonic crystal layer can be adjusted, thereby changing the quality factor of the microcavity.

[0069] The two-dimensional photonic crystal microcavity provided by the present invention can also be applied to fields such as microcavity lasers, microcavity sensors, microcavity filters, and microcavity detectors. Several embodiments are provided below to illustrate this.

[0070] In one embodiment, the two-dimensional photonic crystal microcavity provided by this application can be applied to microcavity lasers. Figure 7 As shown, the first dielectric layer 1 above the photonic crystal layer 2 uses a medium with gain at the center wavelength of the two-dimensional photonic crystal microcavity, thereby achieving optical gain. By configuring the photonic crystal layer 2 with appropriate parameters, optical lasing can be achieved. In another embodiment, the material of the photonic crystal layer 2 can also be an optical gain medium. In this case, the first dielectric layer 1 and the photonic crystal layer 2 use the same medium.

[0071] In one embodiment, the two-dimensional photonic crystal microcavity provided by this application can be applied to a microcavity detector. Figure 8 As shown, the first dielectric layer (not shown) is an air dielectric layer above the photonic crystal layer 2. The photodetector's photosensitive region 10 is provided on the interface between the photonic crystal layer 2 and the second dielectric layer 4. Because the two-dimensional photonic crystal microcavity has a high quality factor, after light passes through the air dielectric layer and enters the photonic crystal layer 2, the photon energy is confined within the microcavity detector. This increases the probability of interaction between the detector's photosensitive region 10 and received photons, thereby improving the detector's detection efficiency.

[0072] It should be noted that in this solution, the photonic crystal layer 2 and the second dielectric layer 4 are placed in direct contact. Figure 8 The photonic crystal layer 2 and the second dielectric layer 4 are separated only to facilitate the structural arrangement of the photosensitive region 10 .

[0073] In one embodiment, the two-dimensional photonic crystal microcavity provided herein can also be used as a microcavity sensor. The two-dimensional photonic crystal microcavity of the present invention has a high quality factor (Q), which means that as a microcavity sensor, it has high wavelength resolution. Therefore, by measuring changes in the central wavelength of the two-dimensional photonic crystal microcavity, the impact of environmental factors such as temperature and humidity on the microcavity can be determined, thereby realizing the application of highly sensitive sensors.

[0074] In summary, the two-dimensional photonic crystal microcavity of the present invention has an extremely high quality factor and excellent optical performance. Its very small size facilitates integration into optical devices and is robust to process errors during processing, facilitating large-scale industrial production. Therefore, the two-dimensional photonic crystal microcavity of the present invention exhibits excellent performance when applied to fields such as semiconductor lasers, microcavity sensors, microcavity filters, and microcavity detectors.

[0075] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments. In the description of this specification, the reference terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification.

[0076] In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they contradict each other. The above is only an embodiment of this specification and is not intended to limit this specification. For those skilled in the art, the embodiments of this specification may be subject to various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of this specification shall be included within the scope defined by the claims of this application.

Claims

1. A two-dimensional photonic crystal microcavity, characterized in that: include: a first dielectric layer, a second dielectric layer, and a photonic crystal layer disposed between the first dielectric layer and the second dielectric layer; The photonic crystal layer is provided with periodically arranged cylindrical through holes, and the cylindrical through holes are perpendicular to the first dielectric layer and the second dielectric layer; The photonic crystal layer includes a central region and a peripheral region; the central region includes Na×Na cylindrical through holes, where Na is a positive integer greater than or equal to 1; the peripheral region wraps the central region, and is used to suppress the energy leakage from the two-dimensional photonic crystal microcavity from the peripheral region or control the energy in the two-dimensional photonic crystal microcavity to radiate toward the peripheral region; the bandgap of the central wavelength of the two-dimensional photonic crystal microcavity can be formed by changing at least one of the distance between adjacent cylindrical through holes in the peripheral region, the radius of the cylindrical through holes in the peripheral region, and the interval between the peripheral region and the central region.

2. The two-dimensional photonic crystal microcavity according to claim 1, characterized in that: The cylindrical through hole can be filled with gas, solid or liquid material.

3. The two-dimensional photonic crystal microcavity according to claim 1, characterized in that: The filling rate and filling shape of the filling material in the cylindrical through hole can be adjusted.

4. The two-dimensional photonic crystal microcavity according to claim 1, characterized in that: The radius of the cylindrical through holes in the peripheral area, the number of the cylindrical through holes and the distance between adjacent cylindrical through holes can all be adjusted.

5. The two-dimensional photonic crystal microcavity according to any one of claims 1 to 4, characterized in that: The size and central wavelength of the two-dimensional photonic crystal microcavity can be adjusted by changing at least one of the size of Na, the distance between adjacent cylindrical through holes in the central region, the radius of the cylindrical through holes in the central region, the thickness of the photonic crystal layer, the refractive index of the filling material in the cylindrical through holes in the central region, and the refractive index of the photonic crystal.

6. The two-dimensional photonic crystal microcavity according to any one of claims 1 to 4, characterized in that: The radiation energy at the contact surface between the photonic crystal layer and the first and second dielectric layers can be adjusted by changing the ratio of the thickness of the photonic crystal layer material to the distance between adjacent cylindrical through holes in the central region and / or the radius of the cylindrical through holes.

7. The two-dimensional photonic crystal microcavity according to any one of claims 1 to 4, characterized in that: The radiation in any direction of the side of the peripheral region of the two-dimensional photonic crystal microcavity can be adjusted by individually changing the radius of the cylindrical through holes and / or the distance between the cylindrical through holes in the peripheral region corresponding to the direction.

8. The two-dimensional photonic crystal microcavity according to any one of claims 1 to 4, characterized in that: The radiation in any side direction of the two-dimensional photonic crystal microcavity can be adjusted by removing individually or partially removing the cylindrical through holes in the peripheral area corresponding to the side direction.

9. The two-dimensional photonic crystal microcavity according to any one of claims 1 to 4, characterized in that: The array formed by the cylindrical through holes is a square array, and the central area is located in the middle of the array; The peripheral area includes four side areas and four corner areas, and the side areas and the corner areas are all rectangular; One of the long sides of the four side areas is equal in length to the four sides of the central area and they are aligned; The four corner regions are respectively located at the four corners of the square array, and two sides of the four corner regions are respectively equal to one short side of two adjacent side regions and are aligned.

10. The two-dimensional photonic crystal microcavity according to claim 9, characterized in that: The four side regions are all rectangular regions formed by an arrangement of Na×Nb cylindrical through holes, wherein Nb is a positive integer greater than or equal to 1.

11. The two-dimensional photonic crystal microcavity according to claim 10, characterized in that: The four corner areas are all square areas formed by an arrangement of Nb×Nb cylindrical through holes, where Nb is a positive integer greater than or equal to 1.

12. A microcavity laser, characterized in that: The two-dimensional photonic crystal microcavity comprises the two-dimensional photonic crystal microcavity according to any one of claims 1 to 10, wherein the first dielectric layer and / or the second dielectric layer in the two-dimensional photonic crystal microcavity is a medium having optical gain at the central wavelength of the microcavity.

13. The microcavity laser according to claim 12, characterized in that: The photonic crystal layer of the two-dimensional photonic crystal microcavity adopts the same optical gain medium as the first medium layer or the second medium layer.

14. A microcavity detector, characterized in that: The two-dimensional photonic crystal microcavity comprises the two-dimensional photonic crystal microcavity according to any one of claims 1 to 10, wherein the first dielectric layer is an air layer, and a photosensitive area is provided between the second dielectric layer and the photonic crystal layer.

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