Surface lens unit, semiconductor laser and preparation method

Abstract

The invention relates to the technical field of semiconductor lasers, in particular to a surface lens unit, a semiconductor laser and a preparation method. The surface lens unit is used for a light output port of the semiconductor laser, and the surface lens unit is an annular structural member. A plurality of ring parts are arranged on the outer side face of the annular structural part, the ring parts are sequentially arranged from the annular structural part to the outside, and the heights of the ring parts are gradually reduced from the annular structural part to the outside. According to the embodiment, the surface lens unit is arranged to be an annular structural part, a stepped structure of a plurality of annular parts is arranged on the outer surface of the annular structure, and the thickness of the stepped structure is gradually decreased from the center of the annular structural part to the outside. The surface lens unit is arranged on a VCSEL laser output hole, an annular structural part of the surface lens unit is arranged on the VCSEL laser output hole, the radial and angular high-order transverse modes of output light are effectively inhibited through the surface lens unit, the laser output efficiency of a single transverse mode is improved, and the surface lens unit can effectively reduce the influence of the heat effect on a VCSEL chip through the annular structure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lasers, and in particular to a surface lens unit, a semiconductor laser and a preparation method thereof. Background Art

[0002] At present, high-speed modulated VCSEL is the research focus of the laser industry. At present, VCSEL with 25GHz bandwidth has been relatively mature, but there are still many challenges in how to further improve the performance of VCSEL. For example, the output light of VCSEL has high-order multi-transverse modes, and the existence of high-order transverse modes will reduce the signal-to-noise ratio and affect the quality of the output light.

[0003] In the process of realizing the present invention, the inventors found that: currently, to control the output beam quality of VCSEL lasers, an external beam controller is often required, which requires some space for the laser and increases the cost. It is difficult to control the output beam of semiconductor lasers without reducing the space and cost. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a surface lens unit, a semiconductor laser and a manufacturing method that overcome the above problems or at least partially solve the above problems.

[0005] In a first aspect, an embodiment of the present invention provides a surface lens unit for a light output port of a semiconductor laser, wherein the surface lens unit is a ring-shaped structural member; A plurality of ring members are arranged on the outer side of the annular structure. The ring members are arranged in sequence outward from the annular structure, and the heights of the ring members gradually decrease outward from the annular structure.

[0006] Furthermore, the height difference of the ring is controlled to be 0.2125-0.25um.

[0007] Furthermore, the inner diameter of the annular structure is controlled to be 4-10 um.

[0008] Furthermore, the number of the rings is controlled to be 4-8.

[0009] Furthermore, the surface lens unit is made of TiO2 or SiN.

[0010] Furthermore, the cross-section of the annular structure includes a circle, a rectangle or a hexagon.

[0011] A second aspect also discloses a semiconductor laser, including: a semiconductor laser light emitting structure having a vertical cavity surface emitting laser structure; The surface lens unit described above, the surface lens unit array forms a surface lens, the surface lens is arranged at the light output port of the semiconductor laser light-emitting structure, and the coupling layer is arranged between the surface lens unit array and the semiconductor laser light-emitting structure.

[0012] Furthermore, the coupling layer is a SiO2 layer, and the thickness of the SiO2 layer is controlled to be 15-25 nm.

[0013] The third aspect also discloses a method for preparing a semiconductor laser, the steps comprising: A coupling layer is plated on the semiconductor laser light emitting structure by a magnetron sputtering process; Plating a coating layer on the coupling layer by a magnetron sputtering process; A mask is manufactured according to a desired pattern, wherein the desired pattern is a ring-shaped body, and the height of the ring-shaped body gradually decreases from the outer surface to the center, forming a trapezoidal structure; The pattern on the mask is etched onto the coating layer by a radio frequency plasma etcher, thereby obtaining a surface lens on the semiconductor laser light-emitting structure; The semiconductor laser light emitting structure is cleaned with a solvent to obtain a semiconductor laser with a surface lens.

[0014] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least: In an embodiment of the present invention, a surface lens unit is provided. Since the intensity of the high-order mode is stronger as it is closer to the light output hole, and weaker as it is farther from the center, the annular structure and the ring member are combined to form a stepped annular lens. The annular lens adopts a structure in which the thickness of the lens decreases in steps from the inside to the outside, that is, the higher the intensity of the high-order mode is closer to the center position of the annular structure, a thicker lens structure is used, while the intensity of the high-order mode is weaker as it is farther from the center, a thinner lens structure is used. This structure can allow a single transverse mode to be efficiently output, thereby reducing the impact of thermal effects on the chip control characteristics as a whole.

[0015] In an embodiment, the surface lens unit is configured as an annular structure, and a stepped structure of multiple rings is arranged on the outer surface of the annular structure, and the stepped structure is configured to gradually decrease in thickness from the center of the annular structure to the outside. The annular structure of the surface lens unit is arranged on the light output hole of the VCSEL laser. In an embodiment, the surface lens unit effectively suppresses the radial and angular high-order transverse modes of the output light, thereby improving the laser output efficiency of the single transverse mode. The surface lens unit here utilizes an annular structure to effectively reduce the influence of thermal effects on the VCSEL chip.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0019] Figure 1 is a schematic diagram of a semiconductor laser according to an embodiment; Figure 2 is a schematic diagram of a semiconductor laser according to a first embodiment of the present invention; Figure 3 is a schematic diagram of a surface lens according to a first embodiment of the present invention; Figure 4 is a corresponding diagram of the lateral size and light field intensity of the output light spot of the first embodiment of the present invention; Figure 5 is a corresponding diagram of the lateral size and light field intensity of the output light spot of the second embodiment of the present invention; Figure 6 is a schematic diagram of a mask according to an embodiment of the present invention; Figure 7 It is a flow chart of a method for preparing a semiconductor laser according to an embodiment of the present invention.

[0020] Indicated in the figure: 100. Semiconductor laser; 110. semiconductor laser light emitting structure; 120. beam shaper; 121. surface lens; 101, substrate; 102, N-type DBR portion; 103, N-electrode; 104, active region layer; 105, P-type DBR portion; 106, P-electrode; 107, surface lens unit; 108, coupling layer; 1070, annular structural member; 1071, ring member; 200, pattern layer; 201, substrate. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0022] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0023] In this application, the word "exemplary" is used to mean "used as an example, illustration, or description." Any implementation described in this application as "exemplary" is not necessarily to be construed as being more preferred or advantageous than other implementations. The following description is given to enable any technician in the field to implement and use the present application. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in the present application.

[0024] VCSEL is a semiconductor laser structure that forms an optical resonant cavity in a direction perpendicular to the semiconductor epitaxial wafer and emits a laser beam perpendicular to the substrate surface. It is widely used in consumer electronics, military, medical and other fields, such as 3D sensing, AR / VR, robots, LiDAR, consumer electronics, intelligent manufacturing, Internet of Things, data centers, etc. Specific applications include intelligent driving, video surveillance, LiDAR, machine vision, gesture recognition, face recognition and other fields.

[0025] See attached Figure 1As shown, as an embodiment, the semiconductor laser light emitting structure may include an N-type DBR portion 102, an active region layer 104, and a P-type DBR portion 105 on a substrate 101. The semiconductor laser light emitting structure may include a III-V compound semiconductor material. For example, the semiconductor laser light emitting structure may include a GaAs-based compound semiconductor material. For example, the semiconductor laser light emitting structure may include at least one of GaInP, AlGaInP, GaAs, GaInAs, AlGaAs, and AlGaInAs.

[0026] As an example embodiment, the substrate 101 may be a semiconductor substrate 101. For example, a Si substrate, a GaAs substrate, etc. may be used as the substrate. If necessary, a buffer layer and a seed layer whose material for forming the semiconductor laser light emitting structure is lattice-matched with the substrate 101 may be provided between the substrate 101 and the semiconductor laser light emitting structure.

[0027] The active region layer 104 may include one or more quantum wells or quantum dots.

[0028] The N-electrode 103 may be disposed on a portion of the N-type DBR portion 102. The active region layer 104 may be provided in a region of the N-type DBR portion 102 that is not occupied by the N-electrode 103. The P-electrode 106 may be disposed on a portion of the P-type DBR portion 105.

[0029] Figure 2 The semiconductor laser light emitting structure shown is only an example and the scope of the present invention is not limited to Figure 2 The semiconductor laser light emitting structure shown in FIG. may include Figure 2 Various additional components / layers not shown.

[0030] In example embodiments, the emitting semiconductor laser 100 has a surface lens, for example, the semiconductor laser light emitting structure may have a VCSEL structure that generates laser light.

[0031] In an exemplary embodiment, a surface lens is provided on the active region layer 104 arranged on the light output side, for example, on a side opposite to the N-type DBR portion 102 with respect to the active region layer 104. By pairing with the P-type DBR portion 105, the surface lens can be used as an upper light shaper forming a cavity of a VCSEL.

[0032] The inventor of this application is continuing to study how to effectively solve the problem of unsatisfactory control of the current semiconductor laser beam quality. The inventor's research at least includes: how to use surface lenses to control the output beam quality of semiconductor lasers, suppress the radial and angular high-order modes of the output light through the surface lens structure, and improve the quality of the beam. After a lot of repeated research, the inventor proposed the surface lens and semiconductor laser of this application.

[0033] Before describing the embodiments of the present invention in detail, the design concept of the present invention is briefly described below. Figure 3 As shown, the present invention designs a surface lens, and the surface lens unit includes an annular structure 1070 and a ring member 1071, wherein the outer side of the annular structure 1070 is provided with a plurality of ring members 1071, and the ring members 1071 are sequentially arranged outward from the annular structure 1070 to form a stepped structure. The radial and angular high-order transverse modes of the output light are effectively suppressed through the surface lens unit, thereby improving the laser output efficiency of the single transverse mode. The surface lens unit here utilizes the annular structure to effectively reduce the influence of thermal effects on the VCSEL chip.

[0034] See attached Figure 2 As shown, in an embodiment of the present invention, a surface lens unit is provided, which is used for the light output port of a semiconductor laser, and the surface lens unit is a ring-shaped structural member 1070; A plurality of ring members 1071 are disposed on the outer side of the annular structure 1070 . The ring members 1071 are sequentially disposed outward from the annular structure 1070 , and the height of the ring members 1071 gradually decreases outward from the annular structure 1070 .

[0035] It is understandable that the current VCSEL output light is more likely to produce multiple transverse modes, and the existence of high-order transverse modes will reduce the signal-to-noise ratio and affect the quality of the output light; at the same time, thermal effects will reduce the modulation speed and bandwidth of the chip.

[0036] Since the intensity of the high-order mode is stronger as it is closer to the light output hole, and weaker as it is farther from the center, the annular structure 1070 and the ring member 1071 are combined to form a stepped annular lens. The annular lens adopts a structure in which the thickness of the lens decreases in steps from the inside to the outside, that is, the higher the intensity of the high-order mode is closer to the center position of the annular structure 1070, the higher the intensity is, and a thicker lens structure is used, while the higher the intensity of the high-order mode is farther away from the center, the thinner the lens structure is used. This structure can allow the single transverse mode to be efficiently output, thereby reducing the impact of thermal effects on the chip control characteristics as a whole.

[0037] In the embodiment, the surface lens unit is configured as an annular structure 1070 , and a stepped structure of multiple rings 1071 is provided on the outer surface of the annular structure. The stepped structure is configured to be arranged on multiple rings 1071 with a thickness gradually decreasing from the center of the annular structure 1070 to the outside.

[0038] The annular structure 1070 of the surface lens unit here is arranged on the light output hole of the VCSEL laser. In the embodiment, the radial and angular high-order transverse modes of the output light are effectively suppressed by the surface lens unit, thereby improving the laser output efficiency of the single transverse mode. The surface lens unit here utilizes the annular structure to effectively reduce the influence of thermal effects on the VCSEL chip.

[0039] See attached Figure 3 As shown, in the embodiment, the height difference of the ring member 1071 is controlled to be 0.2125-0.25 um. The number of the ring members 1071 is controlled to be 4-8. The inner diameter of the annular structure 1070 is controlled to be 4-10 um.

[0040] In an embodiment, the surface lens unit is set to a stepped structure, and the step height difference of the stepped structure is controlled, and the height difference is controlled to be 0.2125um-0.25nm. Through the height difference of the stepped structure and the number of steps, the influence of the radial and angular high-order transverse modes of the output light on the single transverse mode is effectively suppressed. And the inner diameter of the annular structure of the annular structure 1070 is set to 4-10 um, and the size of the inner diameter hole of the annular structure is controlled to ensure that the laser output efficiency of the single transverse mode is improved by the surface lens unit. Here, the surface lens unit uses the annular structure to effectively reduce the influence of thermal effects on the VCSEL chip.

[0041] In some embodiments, the surface lens unit 107 is configured as an annular structure 1070, and a plurality of ring members 1071 arranged in sequence are provided on the outer side of the annular structure 1070, the inner diameter of the annular structure 1070 is 10um, and the plurality of ring members 1071 are six, and the heights of the six ring members 1071 gradually decrease from the annular structure 1070 to the outside, and the height difference of the plurality of ring members 1071 is controlled to be 0.2um; in other embodiments, the surface lens unit 107 is configured as an annular structure 1070, the inner diameter of the annular structure 1070 is 4um, and a plurality of ring members 1071 arranged in sequence are provided on the outer side of the annular structure 1070 , and there are four ring members 1071, the heights of the four ring members 1071 gradually decrease from the annular structure 1070 to the outside, and the height difference of the multiple ring members 1071 is controlled to be 0.22um; in other embodiments, the surface lens unit 107 is set as an annular structure 1070, the inner diameter of the annular structure 1070 is 6um, and the outer side of the annular structure 1070 is provided with a plurality of ring members 1071 arranged in sequence, and there are eight ring members 1071, the heights of the eight ring members 1071 gradually decrease from the annular structure 1070 to the outside, and the height difference of the multiple ring members 1071 is controlled to be 0.4um.

[0042] In a further embodiment, the surface lens unit 107 is made of TiO2 or SiN. The cross section of the annular structure 1070 includes a circle, a rectangle or a hexagon.

[0043] For example: In some embodiments, the surface lens unit 107 is set to a step structure and is made of TiO2, and the cross-section of the step structure is circular, or it is considered to be a circular ring structure; in other embodiments, the surface lens unit 107 is set to a step structure and is made of SiN, and the cross-section of the step structure is rectangular, or it is considered to be a rectangular ring structure; in still other embodiments, the surface lens unit 107 is set to a step structure and is made of SiN, and the cross-section of the step structure is hexagonal, or it is considered to be a hexagonal ring structure.

[0044] Based on the same inventive concept, refer to the attached Figure 2 As shown, a semiconductor laser comprises: a semiconductor laser light emitting structure having a vertical cavity surface emitting laser structure; The surface lens unit 107 described above is arrayed into a surface lens, which is arranged at the light output port of the semiconductor laser light-emitting structure, and a coupling layer, which is arranged between the surface lens unit 107 array and the semiconductor laser light-emitting structure.

[0045] It can be understood that the semiconductor laser emits a laser beam outward, and the surface lens unit 107 suppresses radial and angular high-order transverse modes of the output laser beam, thereby improving the laser output efficiency of a single transverse mode.

[0046] Since the intensity of the high-order mode is stronger as it is closer to the light output hole, and weaker as it is farther from the center, the annular structure 1070 and the ring member 1071 are combined to form a stepped annular lens. The annular lens adopts a structure in which the thickness of the lens decreases in steps from the inside to the outside, that is, the higher the intensity of the high-order mode is closer to the center position of the annular structure 1070, the higher the intensity is, and a thicker lens structure is used, while the higher the intensity of the high-order mode is farther away from the center, the thinner the lens structure is used. This structure can allow the single transverse mode to be efficiently output, thereby reducing the impact of thermal effects on the chip control characteristics as a whole.

[0047] In the embodiment, the surface lens unit 107 is configured as an annular structure 1070, and a stepped structure of multiple rings 1071 is provided on the outer surface of the annular structure, and the stepped structure is configured to gradually decrease in thickness from the center of the annular structure 1070 to the outside.

[0048] The annular structure 1070 of the surface lens unit 107 is arranged on the light output hole of the VCSEL laser. In the embodiment, the surface lens unit 107 effectively suppresses the radial and angular high-order transverse modes of the output light, thereby improving the laser output efficiency of the single transverse mode. The surface lens unit 107 here utilizes the annular structure to effectively reduce the influence of thermal effects on the VCSEL chip.

[0049] By setting a coupling layer between the surface lens and the semiconductor laser light-emitting structure, specifically at the output hole position of the output light of the semiconductor laser light-emitting structure, the coupling layer can effectively reduce the optical coupling between the semiconductor laser light-emitting structure and the surface lens, and at the same time act as a stress relief layer.

[0050] It should be noted that the array of surface lens units 107 here can be one or more. For example, in one embodiment, the array of surface lens units 107 is one, and the one surface lens unit 107 is a surface lens, and the surface lens is arranged at the light output port of the semiconductor laser light-emitting structure, and a coupling layer, and the coupling layer is arranged between the array of surface lens units 107 and the semiconductor laser light-emitting structure; in another embodiment, the array of surface lens units 107 is eight, and the eight surface lens units 107 are surface lenses, and the surface lenses are arranged at the light output port of the semiconductor laser light-emitting structure, and a coupling layer, and the coupling layer is arranged between the array of surface lens units 107 and the semiconductor laser light-emitting structure; in another embodiment, the array of surface lens units 107 is thirty-six, and the thirty-six surface lens units are surface lenses, and the surface lenses are arranged at the light output port of the semiconductor laser light-emitting structure, and a coupling layer, and the coupling layer is arranged between the array of surface lens units and the semiconductor laser light-emitting structure.

[0051] In the embodiment to be explained, the coupling layer is a SiO2 layer, and the thickness of the SiO2 layer is controlled to be 15-25 nm.

[0052] In some embodiments, a SiO2 thin film layer is directly deposited on a patterned VCSEL wafer by a magnetron sputtering process, wherein the thickness of the SiO2 thin film layer is controlled to be 20 nm; in other embodiments, a SiO2 thin film layer is directly deposited on a patterned VCSEL wafer by a magnetron sputtering process, wherein the thickness of the SiO2 thin film layer is controlled to be 16 nm; in some embodiments, a SiO2 thin film layer is directly deposited on a patterned VCSEL wafer by a magnetron sputtering process, wherein the thickness of the SiO2 thin film layer is controlled to be 24 nm.

[0053] It is understandable that the coupling layer may be replaced by a coupling layer made of other materials.

[0054] For example: Figure 4 In one embodiment, the semiconductor laser is not provided with the above-mentioned surface lens unit, that is, the light beam does not pass through the stepped central control structure of the surface lens, and the lateral size of the output light spot and the light field intensity correspond to the figure.

[0055] Figure 5 In one embodiment, the semiconductor laser is provided with the above-mentioned surface lens unit, that is, the light beam passes through the stepped central control structure of the surface lens, and the corresponding diagram of the lateral size of the output light spot and the light field intensity is output.

[0056] In a specific embodiment, the above specific structure is manufactured on the output aperture of the laser, and 20nm SiO2 is selected as the stress relief layer between the bottom layer and the output aperture. The inner diameter of the hollow ring is 6um, the stepped step material is TiO2, the step height is 0.2125um, the single side length difference of each step is 0.2125um, and the number of layers is four. As described above, Figure 4 and Figure 5 The corresponding diagram of the lateral size of the output light spot and the output light field intensity of the 850nm VCSEL laser before and after the structure.

[0057] In summary, it can be seen that the intensity of the light field output by the structure is 3X10 9 times, and the output light field efficiency is greatly improved.

[0058] Furthermore, in the embodiment, the structure of the surface lens adopts a hollow structure design in the middle, so that the semiconductor laser is conducive to the rapid release of heat and reduces the thermal effect.

[0059] Based on the same inventive concept, a method for preparing a surface lens is also disclosed. Figure 7 As shown, the steps include: Step S001: a coupling layer is plated on the semiconductor laser light-emitting structure by a magnetron sputtering process.

[0060] By setting a coupling layer between the surface lens and the semiconductor laser light-emitting structure, specifically at the output hole position of the output light of the semiconductor laser light-emitting structure, the coupling layer can effectively reduce the optical coupling between the semiconductor laser light-emitting structure and the surface lens, and at the same time act as a stress relief layer.

[0061] In the embodiment to be explained, the coupling layer is a SiO2 layer, and the thickness of the SiO2 layer is controlled to be 15-25 nm.

[0062] In some embodiments, a SiO2 thin film layer is directly deposited on a patterned VCSEL wafer by a magnetron sputtering process, wherein the thickness of the SiO2 thin film layer is controlled to be 20 nm; in other embodiments, a SiO2 thin film layer is directly deposited on a patterned VCSEL wafer by a magnetron sputtering process, wherein the thickness of the SiO2 thin film layer is controlled to be 16 nm; in some embodiments, a SiO2 thin film layer is directly deposited on a patterned VCSEL wafer by a magnetron sputtering process, wherein the thickness of the SiO2 thin film layer is controlled to be 24 nm.

[0063] It is understandable that the coupling layer may be replaced by a coupling layer made of other materials.

[0064] Step S002: a coating layer is deposited on the coupling layer by a magnetron sputtering process.

[0065] It can be understood that Si3N4 or TiO2 is coated on the coupling layer by magnetron sputtering process to obtain a coating layer, where the coupling layer is a SiO2 layer, and the thickness of the coating layer is controlled to be 0.85 um.

[0066] It should be noted that the coating layer is one of TiO2 or SiN, for example: In some embodiments, TiO2 is coated on the coupling layer of the semiconductor laser light-emitting structure by a magnetron sputtering process, and the thickness of the coating is controlled to be 0.8um; in other embodiments, TiO2 is coated on the coupling layer of the semiconductor laser light-emitting structure by a magnetron sputtering process, and the thickness of the coating is controlled to be 0.6um; in still other embodiments, TiO2 is coated on the coupling layer of the semiconductor laser light-emitting structure by a magnetron sputtering process, and the thickness of the coating is controlled to be 0.9um.

[0067] Step S003: manufacturing a mask according to a required pattern, wherein the required pattern is a ring-shaped body, and the height of the ring-shaped body gradually decreases from the outer surface to the center, forming a trapezoidal structure.

[0068] It can be understood that in the embodiment, a mask having an annular staircase structure pattern is prepared, and the mask here can refer to the conventional preparation method and will not be repeated here. The pattern here is a staircase structure annular body pattern, and the specific structure of the annular body is an annular body, and the height of the annular body gradually decreases from the outer surface to the center to form a trapezoidal structure.

[0069] It should be noted that the mask here includes a substrate 201 and a pattern layer 200 , and the pattern layer 200 is arranged on one side of the substrate 201 .

[0070] In some embodiments, referring to the attached Figure 6As shown, the pattern layer 200 on the mask plate is a circular ring structure, and the specific structure is that the height of the circular ring structure from the substrate 201 is set to a step structure that gradually decreases from the edge position of the circular ring structure to the center position, which can be considered as a structure in which multiple ring structures with different heights are sequentially fitted and arranged; in other embodiments, the pattern layer 200 on the mask plate is a rectangular ring structure, and the specific structure is that the height of the rectangular ring structure from the substrate 201 is set to a step structure that gradually decreases from the edge position of the rectangular ring structure to the center position, which can be considered as a structure in which multiple ring structures with different heights are sequentially fitted and arranged; in still other embodiments, the pattern layer 200 on the mask plate is a hexagonal ring structure, and the specific structure is that the height of the hexagonal ring structure from the substrate 201 is set to a step structure that gradually decreases from the edge position of the hexagonal ring structure to the center position, which can be considered as a structure in which multiple ring structures with different heights are sequentially fitted and arranged.

[0071] It should be noted that the pattern layer 200 is a film layer made of positive photoresist. The characteristic of positive photoresist is that after the coating is exposed and developed, the exposed part is dissolved and the unexposed part remains. Therefore, when using positive photoresist for photolithography, the photoresist of the exposed part will gradually disappear, while the photoresist of the unexposed part will remain, forming the desired image. The substrate 201 is a quartz plate.

[0072] For example, after the coupling layer is plated, the semiconductor laser light-emitting structure is placed on a fixed frame of a two-photon polymerization device, and a positive photoresist is 3D printed on the upper side of the coupling layer using a two-photon polymerization process, so that a layer of positive photoresist is formed on the upper side of the coupling layer. Here, the upper side of the coupling layer can be considered as the side away from the semiconductor laser light-emitting structure. And when printing, a designed step pattern is reserved at the position corresponding to the light output port of the semiconductor laser light-emitting structure, and other structures are not excluded.

[0073] Step S004: etching the pattern on the mask onto the coating layer by a radio frequency plasma etcher, thereby obtaining a surface lens on the semiconductor laser light-emitting structure.

[0074] It can be understood that the pattern on the mask is etched onto the coating layer by an etching process, so that the coating layer obtains the shape of a surface lens, and a surface lens is obtained on the semiconductor laser light-emitting structure. The structure of the surface lens here corresponds to the pattern layer 200 on the mask. The annular structure 1070 of the surface lens unit here is arranged on the light output hole of the VCSEL laser. In the embodiment, the radial and angular high-order transverse modes of the output light are effectively suppressed by the surface lens unit, and the laser output efficiency of the single transverse mode is improved. The surface lens unit here uses an annular structure to effectively reduce the influence of thermal effects on the VCSEL chip.

[0075] For example, in the embodiment, when the RF plasma etching machine is used for etching, the vacuum degree is controlled at 6*10 -4 , the flow rate is controlled at 500 mA, and the etching time is controlled at about 2 hours. In this way, a surface lens is obtained on the coating layer, wherein the surface lens is a ring structure 1070; a plurality of rings 1071 are arranged on the outer side of the ring structure 1070, and the rings 1071 are arranged outward from the ring structure 1070 in sequence, and the height of the rings 1071 gradually decreases from the ring structure 1070 outward.

[0076] For example: In some embodiments, the annular structure 1070 on the surface lens is a circular ring structure. Specifically, the height of the circular ring structure from the coupling layer is set to a stepped structure that gradually decreases from the center position of the circular ring structure to the edge position. It can be considered that six annular structures with different heights are arranged in sequence, and the step height difference of the stepped structure is controlled to be 0.2nm; In some other embodiments, the pattern layer 200 on the mask is a rectangular ring structure. Specifically, the height of the rectangular ring structure from the substrate 201 is set to a stepped structure that gradually decreases from the center position of the rectangular ring structure to the edge position. It can be considered that a plurality of ring structures with different heights are sequentially bonded and arranged. It can be considered that four ring structures with different heights are sequentially bonded and arranged. The step height difference of the stepped structure is controlled, and the height difference is controlled to be 0.22um. In some further embodiments, the pattern layer 200 on the mask plate is a hexagonal ring structure. Specifically, the height of the hexagonal ring structure from the substrate 201 is set to be a stepped structure that gradually decreases from the center position of the hexagonal ring structure to the edge position. It can be considered as a structure in which multiple ring structures of different heights are sequentially fitted and arranged, or it can be considered as a structure in which eight ring structures of different heights are sequentially fitted and arranged, and the step height difference of the stepped structure is controlled to be 0.4nm.

[0077] Step S005: Clean the semiconductor laser light-emitting structure with a solvent to obtain a semiconductor laser with a surface lens.

[0078] It can be understood that in the embodiment, a solvent is used to clean the semiconductor laser light emitting structure, thereby ensuring that the semiconductor laser light emitting structure is cleaned, thereby obtaining a semiconductor laser having the above-mentioned surface lens.

[0079] In actual work, acetone solution is used to dissolve the positive photoresist. Specifically, the semiconductor laser light-emitting structure is placed in an ultrasonic device and an appropriate amount of acetone solution is added. The cleaning power of the ultrasonic device is set to 20-25W during cleaning, and the cleaning time is controlled within 5-10 minutes, thereby effectively cleaning the impurities 3D printed on the semiconductor laser light-emitting structure and preparing for the next step.

[0080] Based on the same inventive concept, a method for using a semiconductor laser is also disclosed, wherein the semiconductor laser comprises the surface lens described above.

[0081] For example, the surface lens can be used in the fields of plane lenses, holographic optics, autonomous driving, remote sensing, ultra-high resolution imaging, beam generation, polarization devices, etc.

[0082] The specific examples and beneficial effects of the method described in this embodiment can be found in the description of the semiconductor laser mentioned above, and will not be described in detail here.

[0083] Obviously, various changes and modifications may be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various changes and modifications may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. Thus, if these changes and modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A surface lens unit for a light output port of a semiconductor laser, characterized in that: The surface lens unit is an annular structure; A plurality of ring members are arranged on the outer side of the annular structure. The ring members are arranged in sequence outward from the annular structure, and the heights of the ring members gradually decrease outward from the annular structure.

2. The surface lens unit according to claim 1, characterized in that: The height difference of the ring is controlled to be 0.2125-0.25um.

3. The surface lens unit according to claim 1, characterized in that: The inner diameter of the annular structure is controlled to be 4-10um.

4. The surface lens unit according to claim 1, characterized in that: The number of the rings is controlled to be 4-8.

5. The surface lens unit according to claim 1, characterized in that: The surface lens unit is made of TiO2 or SiN.

6. The surface lens unit according to claim 2, characterized in that: The cross section of the annular structure includes a circle, a rectangle or a hexagon.

7. A semiconductor laser, characterized in that: include: A semiconductor laser light emitting structure having a vertical cavity surface emitting laser structure; The surface lens unit described in claims 1-6, the surface lens unit array forms a surface lens, the surface lens is arranged at the light output port of the semiconductor laser light-emitting structure, and a coupling layer is arranged between the surface lens unit array and the semiconductor laser light-emitting structure.

8. The semiconductor laser according to claim 7, characterized in that The coupling layer is a SiO2 layer, and the thickness of the SiO2 layer is controlled to be 15-25 nm.

9. A method for preparing a semiconductor laser, characterized in that the steps include: A coupling layer is plated on the semiconductor laser light emitting structure by a magnetron sputtering process; Plating a coating layer on the coupling layer by a magnetron sputtering process; A mask is manufactured according to a desired pattern, wherein the desired pattern is a ring-shaped body, and the height of the ring-shaped body gradually decreases from the outer surface to the center, forming a trapezoidal structure; The pattern on the mask is etched onto the coating layer by a radio frequency plasma etcher, thereby obtaining a surface lens on the semiconductor laser light-emitting structure; The semiconductor laser light emitting structure is cleaned with a solvent to obtain a semiconductor laser with a surface lens.

10. The method for preparing a semiconductor laser according to claim 9, characterized in that: The thickness of the coupling layer is controlled to be 20-25 nm.

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