Fabry-Perot microcavity laser based on low-light-level element and light field test system
By integrating micro-optical elements into a Fabry-Perot microcavity laser and employing laser nano-direct writing technology, the problems of high cost and complex processes have been solved, achieving high-precision, low-cost optical field modulation and detection, and achieving subwavelength precision dynamic modulation effects.
Patent Information
- Application Number
- CN202520594632.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2026-04-03
- Estimated Expiration
- 2035-04-01
Smart Images
Figure CN224082918U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of optical field modulation technology, specifically relating to a Fabry-Perot microcavity laser based on micro-optical elements and an optical field testing system. Background Technology
[0002] Spatial shaping of laser beams is a core topic in modern optical research. The unique properties of Fabry-Perot optical microcavities (such as subwavelength mode volume and ultra-high quality factor Q) bring new challenges and opportunities to optical field manipulation. Traditional microcavities mainly rely on external passive generation and manipulation of the optical field. External beam shaping requires the introduction of discrete amplitude or phase elements, leading not only to additional insertion loss and inherent stray light problems, but also to increased optical path complexity. This limits the integration and stability of optical components at the micro / nano scale, making high-efficiency manipulation difficult. To overcome the limitations of separating the fixed resonant cavity from external beam shaping, the optical field manipulation mechanism of micro / nano optical microcavities has gradually evolved from passive to active cavities, embedding the optical field manipulation function into the resonant cavity's eigenmodes and reconstructing the interaction paradigm between photons and the resonant cavity. By directly integrating tunable materials or dynamic microstructures at the micro / nano scale, the target optical field can be reconstructed in real time during resonance, forming an integrated cavity-as-a-system design. This cavity mode trimming strategy not only avoids the efficiency loss caused by external shaping, but also achieves dynamic control with subwavelength precision through the strong local field interaction between the cavity mode and the control element.
[0003] Currently, there are several active Fabry-Perot microcavity (Fabry-Perot) fabrication strategies: First, intracavity integration, which introduces focusing elements such as microspheres and microbubbles within the cavity to achieve mode field constraint; however, this approach suffers from significant defects in dynamic stability and process repeatability, limiting structural designability and degrees of freedom. Second, plano-concave microcavities, which utilize focused ion beam milling, laser ablation, and thin-film deposition techniques to construct curved cavity mirrors; while achieving high Q values and ultra-small mode volumes, precision surface fabrication relies on expensive equipment and is difficult to customize complex surfaces. Third, field engineering strategies for controlling cavity surface microstructures, which construct subwavelength structures such as metasurfaces or bipolar integrated circuits (BICs) to control parameters such as optical field topological charge and polarization state; these strategies also require expensive and complex processes and generally suffer from the contradiction between high degrees of freedom and low Q values. Therefore, developing micro / nano precision fabrication schemes that combine high precision and low cost to achieve precise and coordinated control of the optical properties and functional design of Fabry-Perot microcavities is of great significance. Summary of the Invention
[0004] The purpose of this invention is to provide a high-precision, low-cost Fabry-Perot microcavity laser based on micro-optical elements and an optical field testing system for use in optical field modulation and detection.
[0005] The Fabry-Perot microcavity laser based on micro-optical elements provided by this utility model comprises: two planar mirrors, namely a first planar mirror and a second planar mirror, a spacer, and a laser gain medium; wherein, the surfaces of the first and second planar mirrors are coated with a high reflectivity thin film, and the surface of the second planar mirror is fabricated with micro-optical elements; the first and second planar mirrors are placed parallel to each other, the spacer has the same diameter and is located at the four corners of the two planar mirrors, separating the two planar mirrors, the surface of the second mirror with micro-optical elements (i.e., micro / nano devices) faces into the microcavity, and the laser gain medium is sandwiched in the center of the two planar mirrors; after applying a certain pressure to keep the two planar mirrors highly parallel, the two planar mirrors are bonded and fixed to form a Fabry-Perot structure laser resonator cavity with integrated micro-optical elements.
[0006] Furthermore:
[0007] The aforementioned plane mirror uses quartz glass as a substrate and is coated with a high-reflectivity dielectric film, with a reflectivity greater than 99.5%.
[0008] The spacer is a polystyrene microsphere;
[0009] The laser gain medium is a liquid dye soluble in water or organic solvents (such as sodium fluorescein, FITC and other green fluorescent dyes, R6G red fluorescent dye).
[0010] The intracavity micro-optical element is a refractive freeform surface element, a diffractive element, or a hybrid refractive / diffractive element based on a transparent medium material. Further, the continuous freeform surface element mainly includes spherical microlenses and axial cones (see...). Figure 1 (a) and (d)), the diffraction element is a phase zone plate (see [reference]). Figure 1 (b) The refractive / diffractive hybrid element is a resonant diffractive lens (see [link]). Figure 1(c) The spherical microlens is a plano-convex lens that focuses light by refraction; the phase zone plate is composed of alternating concentric rings, with both odd and even rings remaining optically transparent. This periodic diffraction structure can adjust the phase of the incident light, allowing different diffraction orders to coherently interfere on the focal plane, forming a high-intensity focal point; the harmonic diffraction lens combines the advantages of refractive and diffractive lenses, maintaining the thinness of a diffractive lens and the high energy concentration efficiency of a refractive lens while overcoming the dispersion variation of the focal length at discrete wavelengths; the axial cone can convert a plane wave into an approximately diffraction-free Bessel beam, producing a maximum collimation distance without diffraction. The spherical microlens and phase zone plate harmonic diffraction lenses are focusing elements. Different focal lengths correspond to different light field constraint effects, which can be used to controllably constrain the light field mode within the cavity, localize the light field, and thus enhance the interaction between light and matter. The axial cone is a shaping micro-optical element used to shape the light field within the cavity into structured light in a Bessel-Gaussian mode. The spherical microlens, by controlling the relative position of the center of the microlens and the center of the pump beam, is used to achieve the emission of higher-order laser modes of different orders.
[0011] The fabrication of the Fabry-Perot microcavity surface micro / nano devices is performed using laser nano-direct writing technology, and the specific steps are as follows:
[0012] S1: Cleaning: Clean the plane mirror thoroughly and dry it;
[0013] S2: Spin coating: Spin coat a layer of photoresist onto the surface of the plane mirror and dry it;
[0014] S3: Laser Direct Writing: Printing the three-dimensional structure of a designed device onto the surface of a planar mirror using laser direct writing technology;
[0015] S4: Post-baking: Further cross-linking and curing of the photoresist in the exposed area;
[0016] S5: Development: The plane mirror is placed in a special developing solution to remove the uncrosslinked photoresist;
[0017] S6: Drying: Use nitrogen gas to blow away the developer on the surface, completing the device processing on the surface of the endoscope.
[0018] The laser nano-direct writing technology described above can realize true three-dimensional, high-fidelity micro-nano device fabrication;
[0019] The configuration (e.g., plano-convex or relief-shaped) and parameters (e.g., focal length) of the intracavity device can be quantitatively customized using laser nano-direct writing technology.
[0020] The customized intracavity device further enables quantitative customization of the intracavity optical field.
[0021] This invention also provides an optical field testing system based on the aforementioned Fabry-Perot laser, as shown in the attached figure. Figure 2 As shown, the system includes: a pump laser 7, a neutral density filter 8, a first beam splitter 9, a second beam splitter 10, a focusing objective lens 11, a Fabry-Perot microcavity laser (also known as an integrated microcavity device) 12, a sample stage 13, an imaging lens 14, a first long-pass filter 15, a CMOS camera 16, a focusing lens 17, a second long-pass filter 18, a spectrometer 19, and a photoelectric energy meter 20; wherein the imaging lens 14, the first long-pass filter 15, and the CMOS camera 16 form the imaging optical path, and the focusing lens 17, the second long-pass filter 18, and the spectrometer 19 form the spectral detection optical path; wherein:
[0022] Pump laser 7 emits pump light, which passes through neutral density filter 8 and is split into two beams by first beam splitter 9. One beam is incident on photoelectric energy meter 20, and the other beam is incident on second beam splitter 10 and focusing objective lens 11 and coupled into integrated microcavity device 12. After the integrated microcavity device 12 and pump light are aligned by sample stage 13, integrated microcavity device 12 generates lasing. The lasing light is reflected back along the original path and received again by focusing objective lens 11. Then it is split into two paths by second beam splitter 10. One path images the lasing light field information through imaging lens 14 and first long-pass filter 15 and is imaged on CMOS camera 16. The other path directly passes through first beam splitter 9 and is incident on spectral detection light path. After passing through focusing lens 17 and second long-pass filter 18, it enters spectrometer 19, where spectrometer 19 receives lasing spectral signals.
[0023] The pump laser is used to emit pump light;
[0024] The neutral density filter is used to regulate the energy of the emitted pump light.
[0025] The focusing objective lens is used to couple the pump light source into the integrated microcavity device, and at the same time collect the output light signal of the lasing for imaging and spectral detection;
[0026] The focusing objective lens is used to couple the lasing signal light into the spectrometer;
[0027] The aforementioned spectrometer is used to collect the emitted spectral signals;
[0028] The imaging lens and imaging objective are used to efficiently transmit the light field image to the CMOS camera;
[0029] The long-pass filter is used to block short-wavelength pump light from passing through and select long-wavelength lasing light to pass through.
[0030] The CMOS camera is used to image the light field and the entire microcavity integrated device.
[0031] The sample stage is used to fix, position, and move the integrated microcavity sample;
[0032] The aforementioned optical energy meter is used to detect the energy of the pump laser.
[0033] The optical field testing system based on the Fabry-Perot laser of this invention can be used for optical field testing and modulation, specifically:
[0034] (1) In the optical field testing system, the output laser pattern is monitored, the position of the dye laser resonator is adjusted, and the micro-optical element in the cavity is moved toward the center of the laser beam or made to have a certain displacement with the pump beam center until the detection system detects the output lasing spot. The generated lasing spot has a smaller mode volume and a special spot mode compared with the traditional planar microcavity without cavity devices. The optical field is controlled and modulated in the cavity.
[0035] (2) In the optical field testing system, monitor the output laser spectrum, adjust the position of the dye laser resonator, move the micro-optical element in the cavity toward the center of the laser beam or make it displaced from the center of the pump beam until the detection system detects the output lasing spectrum. Further adjustment of the pump energy can obtain the relationship between the spectral integral and the pump energy, i.e., the lasing threshold curve of the microcavity.
[0036] The technical principle and effects of this utility model are as follows:
[0037] Fabry-Perot microcavity-based microlasers mainly consist of three elements: a laser cavity, a gain medium, and a pump source. When light is incident on the microcavity, due to multiple reflections and interference from the mirrors, only light of a specific wavelength can form a stable standing wave mode, i.e., a resonant mode, within the cavity. The field distribution of a traditional Fabry-Perot cavity is determined by the cavity length and mirror curvature. However, the micro-optical element of this invention is directly integrated onto the cavity mirror surface, and the optical field distribution within the cavity is altered through local refractive index modulation (e.g., microlenses) or phase modulation (e.g., phase zone plates). By designing the matching relationship between the micro / nano structure dimensions and the microcavity dimensions in the microcavity laser, this invention can achieve modulation of the intracavity optical field, thereby realizing a high-quality factor microcavity laser and customized output of the optical field for specific laser modes. Attached Figure Description
[0038] Figure 1 This is a schematic diagram of a Fabry-Perot microcavity laser structure based on intracavity element integration, along with optical micrographs of different intracavity devices. (a) to (d) represent four different Fabry-Perot microcavity lasers with integrated intracavity devices, respectively.
[0039] Figure 2 It is a system for detecting the optical field and spectrum of a Fabry-Perot harmonic laser with integrated intracavity components.
[0040] Figure 3 This is a characterization of the optical performance of a Fabry-Perot microcavity with an integrated refractive spherical lens. In the figure, (a) to (c) represent the lasing spectra at different cavity lengths, with the corresponding lasing field images inserted. The white dashed line is the outline of the fabricated structure. (d) shows the relationship between the spectral integral and the pump energy at different cavity lengths.
[0041] Figure 4 This is a characterization of the optical performance of a Fabry-Perot microcavity with an integrated phase zone plate. In the figure, (a) to (c) represent the lasing spectra at different cavity lengths, and the corresponding lasing field images are inserted. The white dashed line is the outline of the fabricated structure. (d) shows the relationship between the spectral integral and the pump energy at different cavity lengths.
[0042] Figure 5 This is a characterization of the optical performance of the Fabry-Perot microcavity with an integrated resonant diffraction lens. In the figure, (a) to (c) represent the lasing spectra at different cavity lengths, and the corresponding lasing field images are inserted. The white dashed line is the outline of the fabricated structure. (d) shows the relationship between the spectral integral and the pump energy at different cavity lengths.
[0043] Figure 6 This is a characterization of the optical performance of the Fabry-Perot microcavity with an integrated axial cone mirror. Among them, (a) is the lasing spectrum of a cavity with a length of 50 μm, (b) is the corresponding lasing field image, and (c) is the relationship between its spectral integral and pump energy.
[0044] Figure 7 These are images of the lasing field relative to the pump beam center at different off-axis amounts for a Fabry-Perot microcavity with an integrated intracavity refracting spherical lens.
[0045] Figure 8 This is the fabrication process of intracavitary components.
[0046] The labels in the diagram are as follows: 1 is a plane mirror; 2 is a gain medium; 3 is a refracting spherical lens; 4 is a phase zone plate; 5 is a harmonic diffraction lens; 6 is an axonocone; 7 is a pump laser; 8 is a neutral density filter; 9 is a beam splitter; 10 is a beam splitter; 11 is a focusing objective; 12 is an integrated microcavity device; 13 is a sample stage; 14 is an imaging objective; 15 is a long-pass filter; 16 is a CMOS camera; 17 is a focusing lens; 18 is a long-pass filter; 19 is a spectrometer; 20 is a light energy meter; 21 is a SU-8; 22 is a processing objective; 23 is a femtosecond focusing beam; 24 is a coverslip; 25 is a structure for importing processing programs; 26 is a developing solution. Detailed Implementation
[0047] The present invention will be further described below with reference to the embodiments and accompanying drawings.
[0048] Example 1: A Fabry-Perot microcavity laser based on micro-optical elements is constructed. Its structure includes: two high-reflectivity plane mirrors, designated as a first plane mirror and a second plane mirror, polystyrene microspheres, and a gain dye. The first and second plane mirrors are placed parallel to each other. The polystyrene microspheres, having the same diameter, are dispersed at the four corners of the two plane mirrors as spacers. The device fabricated on the surface of the second mirror is located inside the microcavity. The gain medium is sandwiched between the two plane mirrors. After applying pressure to maintain the two plane mirrors at a high degree of parallelism, they are bonded and fixed together, forming a Fabry-Perot structure dye laser resonator integrated with micro-optical elements.
[0049] The first and second plane mirrors are based on quartz glass and coated with a high-reflectivity dielectric film, with a reflectivity of up to 99.7%. The plane mirrors have a reflection band of 500nm-600nm and a transmission band of 440nm-480nm (transmittance greater than 90%).
[0050] The laser gain medium is a 5mM sodium fluorescein aqueous dye.
[0051] The polystyrene microspheres are selected with diameters of 30, 50, and 80 μm, thus enabling the fabrication of three integrated Fabry-Perot microcavities with cavity lengths of 30, 50, and 80 μm.
[0052] The intracavity micro-optical element is a refracting spherical lens based on SU-8 polymer with a focal length of 50μm and a thickness of 5μm.
[0053] Example 2: Constructing an optical field detection system. This system includes: a pump laser 7, a neutral density filter 8, a beam splitter 9, a beam splitter 10, a focusing objective lens 11, a Fabry-Perot microcavity laser (also known as an integrated microcavity device) 12, a sample stage 13, an imaging lens 14, a long-pass filter 15, a CMOS camera 16, a focusing lens 17, a long-pass filter 18, a spectrometer 19, and a photometer 20. The imaging lens 14, long-pass filter 15, and CMOS camera 16 form the imaging optical path, while the focusing lens 17, long-pass filter 18, and spectrometer 19 form the spectral detection optical path.
[0054] Pump laser 7 emits pump light, which is coupled into integrated microcavity device 12 after passing through beam splitter 9, beam splitter 10, and focusing lens 11. The light emitted by integrated microcavity device 12 is reflected back and split into two paths by beam splitter 9. One path sends the lasing field image information to the imaging optical path, and the other path serves as a signal sent to the spectral detection optical path. In the experimental system, the pump laser is a 473nm nanosecond laser, the focusing lens is 20x magnification, the spectrometer is a fiber optic spectrometer, and the long-pass filter has a cutoff wavelength of 500nm.
[0055] For the optical characteristic analysis of a plano-convex spherical lens, based on the principles of geometric optics, the mathematical expression for its focal length can be stated as:
[0056] ;
[0057] in, n 2. Characterizing the refractive index of the environmental medium. R The radius of curvature of the convex surface of the lens. n L This refers to the refractive index of the lens material. From the stability analysis of the resonant cavity in geometric optics, we know that when 0 ≤ L ≤ f A time-lapse microlens integrated with a Fabry-Perot microcavity can achieve stable resonance, i.e. f This determines the cavity length necessary to achieve stability and optical field confinement. Derived from the four-level equation, the integrated cavity quality factor without gain is approximately 1.5 × 10⁻⁶. 5 (Cavity length is 30μm).
[0058] Example 3: The light field detection system is used for light field detection and modulation;
[0059] (1) Monitor the output laser pattern, adjust the position of the integrated microcavity device, and move the refracting spherical lens toward the center of the laser beam. When the cavity length is set to 30 micrometers, the system detects an output mode with an extremely small lasing spot (diameter ~2μm). See Figure 3 -a,b, the generated lasing spot has a smaller mode volume and fundamental mode output characteristics compared to traditional planar microcavities without cavity devices; when set at a cavity length of 50 micrometers, a lasing spot (diameter ~5μm) with mode volume starting to diverge and increase but still having fundamental mode characteristics is detected; when set at a cavity length of 80 micrometers, a lower pump energy level cannot generate lasing.
[0060] (2) Monitor the output laser spectrum, adjust the position of the integrated microcavity device, and move the refracting spherical lens toward the center of the laser beam. The system detects the output spectrum at cavity lengths of 30, 50, and 80 micrometers. Then, adjust the pump energy and record the spectra at different pump energies to obtain the relationship curves between the spectral integral and the pump energy at different cavity lengths. (See...) Figure 3 -d, when the cavity length is less than or equal to the designed focal length, the integrated microcavity of the refracting spherical mirror has an extremely small lasing threshold, such as Figure 3 -b.
[0061] Example 4, based on the parameters of Example 1, only the following conditions were changed: the intracavity micro-optical element is a phase zone plate with a designed focal length of 50 μm based on SU-8 polymer, and its lasing optical performance results are shown in […]. Figure 4Stable lasing was achieved under conditions where the cavity length was less than the focal length, the cavity length was equal to the focal length, and the cavity length was greater than the focal length. The optical field was confined to the central annular region of the phase zone plate, and the lasing spectrum generally remained in single-mode output. The extremely low threshold condition corresponded to an ultra-high Q value.
[0062] For the optical characteristic analysis of a phase zone plate, its focal length can be expressed mathematically as follows:
[0063] ;
[0064] The mathematical expression for the thickness of a phase zone plate is:
[0065] ;
[0066] In this design, N=3.
[0067] The multi-level diffraction and long depth of focus of the phase zone plate increase its overlap with the gain medium and the fundamental mode, making its microcavity optical field stabilization capability more stable. Derived from the four-level equation, the integrated cavity quality factor without gain is approximately 7.2 × 10⁻⁶. 4 (Cavity length is 30μm).
[0068] Example 5, based on the parameters of Example 1, only the following conditions were changed: the intracavity micro-optical element is a harmonic diffraction lens based on SU-8 polymer with a designed focal length of 50μm, and its lasing optical performance results are shown in […]. Figure 5 Stable lasing was achieved under conditions where the cavity length was less than the focal length, the cavity length was equal to the focal length, and the cavity length was greater than the focal length, with the light field confined to the central region.
[0069] A resonant diffractive lens, positioned between a refracting lens and a diffractive lens, is structured by subtracting multiple steps from the profile of an aspherical lens with a designed focal length of 50 μm. Derived from the four-level equation, the integrated cavity quality factor without gain is approximately 2.4 × 10⁻⁶. 5 (Cavity length is 30μm).
[0070] Example 6, based on the parameters of Example 1, only the following conditions were changed: the intracavity micro-optical element is an axial cone mirror based on SU-8 polymer, with a diameter of 20 μm and a height of 6 μm. Its lasing optical performance results are shown in […]. Figure 6 By bringing the axial cone mirror close to the center of the laser spot, Bessel-Gaussian mode laser output can be achieved. Figure 6 a,b), while simultaneously achieving an ultra-low pump threshold of ~2uJ / mm 2 ( Figure 6 c).
[0071] The maximum collimation distance of the axial cone mirror is: ;
[0072] in, aFor radius, n 1 represents the refractive index of the lens. n 2 represents the environmental refractive index. α Let be the base angle of the axial conical mirror. When the maximum collimation distance is greater than the cavity length, the integrated microcavity can achieve stable lasing and optical field modulation of the intracavity Bessel-Gaussian beam. Derived from the four-level equation, the quality factor of the integrated cavity without gain is approximately 2.3 × 10⁻⁶. 4 .
[0073] Example 7, based on the parameters of Example 1, only the following conditions were changed: the intracavity micro-optical element is a refracting spherical lens with a focal length of 100 μm based on SU-8 polymer, and its lasing optical performance results are shown in […]. Figure 7 To demonstrate the method's ability to control higher-order Gaussian modes, only a few classic laser output modes are selected here. By controlling the off-axis displacement, i.e., the position of the element center relative to the pump beam center, HG can be obtained when the displacement Δx = -1.21μm and Δy = 0.15μm. 1,0 The pattern; HG will be obtained when the displacement Δx = 0.87 μm and Δy = -1.24 μm. 0,1 The pattern; HG will be obtained when the displacement Δx = -7.74 μm and Δy = 0.62 μm. 19,0 The pattern; HG is obtained when the displacement Δx = 0.21 μm and Δy = 6.94 μm. 0,12 The pattern; HG will be obtained when the displacement Δx = 2.85 μm and Δy = -2.12 μm. 4,2 The pattern; HG is obtained when the displacement Δx = 4.49 μm and Δy = -2.65 μm. 9,4 The system achieves a maximum order of 19. For the spherical lens, the larger the size, the higher the achievable order. By controlling the off-axis pump, the overlap ratio of the pump and different mode distributions can be varied to produce the desired high-order modes.
[0074] Example 8: Fabrication of micro-optical elements in the Fabry-Perot microcavity laser of Example 1 of this utility model, such as... Figure 7 This includes the following steps:
[0075] S1: Cleaning: Take a plane mirror and clean it with acetone, isopropanol and deionized water for 10 minutes each.
[0076] S2: Spin coating: Place a drop of SU-8 photoresist in the center of the surface of the plane mirror in S1, spin coat at 500 rpm for 10 seconds to distribute the photoresist evenly, then spin coat at 1500 rpm for 30 seconds to form a film with a thickness of about 80 micrometers. Place the coated mirror on a hot plate and bake at 65°C for 5 minutes, then bake at 95°C for 20 minutes to allow the photoresist layer to initially cure and remove the solvent.
[0077] S3: Laser Direct Writing: Import the designed device structure STL file into the program, and use a femtosecond laser direct writing device (wavelength 780nm, pulse width 100fs) to process microstructures on the surface of the plane mirror in S2. The processing objective is 100x, the laser power is set to 3mW, and the scanning speed is 60mm / s.
[0078] S4: Post-baking: Place the S3 flat mirror on a hot plate and bake at 95°C for 10 minutes to promote photochemical reaction and cross-linking;
[0079] S5: Development: Immerse the plane mirror of S4 in SU-8 developer, let it stand for 2 minutes to remove the photoresist in the unexposed area, and then clean it with isopropanol;
[0080] S6: Drying: Use nitrogen gas to blow away the developer on the surface, completing the device processing on the surface of the endoscope.
[0081] In summary, this invention achieves precise and coordinated control of the optical properties and functional design of the Fabry-Perot microcavity through a high-precision, low-cost micro-nano precision fabrication scheme.
Claims
1. A Fabry-Perot microcavity laser based on micro-optical elements, characterized in that, Its structure includes: two planar mirrors, spacers, and a laser gain medium; wherein, the surfaces of the two planar mirrors are coated with a high-reflectivity thin film, and one of the planar mirrors has a micro-optical element fabricated on its surface; the two planar mirrors are placed parallel to each other, and the spacers have the same diameter and are located at the four corners of the two planar mirrors, separating the two planar mirrors, with the surface of the micro-optical element facing into the microcavity; the laser gain medium is sandwiched in the center of the two planar mirrors; after applying a certain pressure to keep the two planar mirrors highly parallel, the two planar mirrors are bonded and fixed to form a Fabry-Perot structure laser resonator cavity with integrated micro-optical elements.
2. The Fabry-Perot microcavity laser based on micro-optical elements according to claim 1, characterized in that: The plane mirror uses quartz glass as a substrate and is coated with a high-reflectivity dielectric film with a reflectivity greater than 99.5%. The spacer is polystyrene microspheres; The laser gain medium is a liquid dye that is soluble in water or organic solvents.
3. The Fabry-Perot microcavity laser based on micro-optical elements according to claim 2, characterized in that, The intracavity micro-optical element is a refractive freeform surface element, a diffractive element, or a refractive / diffractive hybrid element based on a transparent medium material; specifically, the freeform surface element is a spherical microlens and an axonocone, the diffractive element is a phase zone plate, and the refractive / diffractive hybrid element is a harmonic diffraction lens; the spherical microlens is a plano-convex lens; the phase zone plate is composed of alternating concentric rings, with both odd and even rings remaining optically transparent.
4. A light field testing system based on the Fabry-Perot microcavity laser according to any one of claims 1-3, characterized in that, include: Pump laser (7), neutral density filter (8), first beam splitter (9), second beam splitter (10), focusing objective (11), Fabry-Perot microcavity laser (also known as integrated microcavity device) (12), sample stage (13), imaging lens (14), first long-pass filter (15), CMOS camera (16), focusing lens (17), second long-pass filter (18), spectrometer (19), and photoelectric energy meter (20); among which, the imaging lens (14), the first long-pass filter (15), and the CMOS camera (16) form the imaging optical path, and the focusing lens (17), the second long-pass filter (18), and the spectrometer (19) form the spectral detection optical path; among which: The pump laser (7) emits pump light, which passes through the neutral density filter (8) and is split into two beams by the first beam splitter (9). One beam is incident on the photoelectric energy meter (20), and the other beam is incident on the second beam splitter (10) and the focusing objective (11) and then coupled into the integrated microcavity device (12). After the integrated microcavity device (12) and the pump light are aligned by the sample stage (13), the integrated microcavity device (12) generates lasing. The lased light is reflected back along the original path and refocused. The objective lens (11) receives the light and then splits it into two paths by the second beam splitter (10). One path images the lasing field image information onto the CMOS camera (16) after passing through the imaging lens (14) and the first long-pass filter (15). The other path passes directly through the first beam splitter (9) and is incident on the spectral detection optical path. It then passes through the focusing lens (17) and the second long-pass filter (18) before entering the spectrometer (19). The spectrometer (19) receives the lasing spectral signal. The pump laser is used to emit pump light; The neutral density filter is used to regulate the energy of the emitted pump light. The focusing objective lens is used to couple the pump light source into the integrated microcavity device, and at the same time collect the output light signal of the lasing for imaging and spectral detection; The focusing objective lens is used to couple the lasing signal light into the spectrometer; The aforementioned spectrometer is used to collect the emitted spectral signals; The imaging lens and imaging objective are used to efficiently transmit the light field image to the CMOS camera; The long-pass filter is used to block short-wavelength pump light from passing through and select long-wavelength lasing light to pass through. The CMOS camera is used to image the light field and the entire microcavity integrated device. The sample stage is used to fix, position, and move the integrated microcavity sample; The aforementioned optical energy meter is used to detect the energy of the pump laser.