Compact high-power semiconductor pumping solid laser

Abstract

The invention discloses a compact high-power semiconductor pump solid laser, which comprises a stimulated radiation mechanism, a coupling mechanism arranged at one end of the stimulated radiation mechanism and an adjusting mechanism arranged on the circumference of the stimulated radiation mechanism, and is characterized in that the stimulated radiation mechanism comprises a radiation cavity and a lens group arranged on the inner side of the radiation cavity; the gain medium is arranged between the lens groups; the coupling mechanism is arranged at one end of the lens group; a flow channel is formed in the inner side of the circumferential cavity wall of the radiation cavity; the coupling mechanism comprises a pump light source and a focus lens group arranged at one end of the pump light source; the focusing lens group is in sliding connection with the radiation cavity, and an adjusting system is arranged in the micro-fluidic chip; therefore, the situation that under high-power pumping, a large amount of heat is generated after the laser crystal absorbs the pumping light, the temperature of the crystal rises, and then the output performance and stability of the laser are affected is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field related to semiconductor lasers, and in particular to a compact high-power semiconductor pumped solid-state laser. Background Art

[0002] With the rapid development of science and technology, laser technology, as an important branch of modern high technology, plays an increasingly important role in scientific research, industry, medical treatment, communication and other fields. As a new type of laser, Diode Pump Solid State Laser (DPSS Laser) has been rapidly developed and widely used in the world in recent years due to its significant advantages such as high efficiency, long life, high beam quality, good stability and compact structure. During the operation of the laser, the crystal (usually the gain medium) will generate heat due to the absorption of pump light. If this heat cannot be effectively dissipated, it will cause the crystal temperature to rise, which will affect the performance of the laser, such as beam quality, output power stability, etc. At the same time, as an important optical component in the laser, the position of the lens (i.e., the distance from the crystal) has an important influence on the focusing effect of the pump light, the excitation efficiency of the gain medium and the light field distribution in the resonant cavity. Summary of the invention

[0003] The invention overcomes the shortcomings of the prior art and provides a compact high-power semiconductor pumped solid-state laser.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a compact high-power semiconductor pumped solid-state laser, comprising: a stimulated radiation mechanism, a coupling mechanism arranged at one end of the stimulated radiation mechanism, and an adjustment mechanism arranged on the circumference of the stimulated radiation mechanism,

[0005] The stimulated radiation mechanism comprises: a radiation cavity, a lens group arranged inside the radiation cavity, and a gain medium arranged between the lens groups; a coupling mechanism is arranged at one end of the lens group, and a flow channel is opened inside the circumferential cavity wall of the radiation cavity;

[0006] The coupling mechanism includes: a pump light source, and a focusing lens group arranged at one end of the pump light source; the focusing lens group is slidably connected with the radiation cavity, and the inner side of the focusing lens group is filled with nitrogen that can absorb heat expansion;

[0007] The regulating mechanism comprises: a nitrogen tank threadedly connected to the radiation cavity; a gas storage cavity is arranged at the bottom in the middle of the focusing lens group, a plurality of microfluidic chips are arranged in the radiation cavity, and a regulating system is arranged in the microfluidic chip.

[0008] In a preferred embodiment of the present invention, the lens group includes a semi-reflective lens and a total reflection lens, the gain medium is arranged in the middle position between the semi-reflective lens and the total reflection lens, and the semi-reflective lens and the total reflection lens form a resonant cavity.

[0009] In a preferred embodiment of the present invention, the coupling mechanism is disposed at one end close to the total reflection lens, and the light generated by the coupling mechanism can be incident from one side of the total reflection lens into the lens group to excite the gain medium.

[0010] In a preferred embodiment of the present invention, the radiation cavity is cylindrical, the flow channel is opened inside the radiation cavity, the flow channel is nested in a plurality of ellipses of different sizes, the flow channel is located on top of the lens group and the coupling mechanism, and a coolant is arranged in the flow channel.

[0011] In a preferred embodiment of the present invention, the focusing lens group includes a first focusing lens and a second focusing lens, the first focusing lens is fixedly connected to the radiation cavity, the second focusing lens is slidably connected to the radiation cavity, and nitrogen is filled between the first focusing lens and the second focusing lens.

[0012] In a preferred embodiment of the present invention, the pump light source emits pump light which is focused and shaped by a focusing lens group to form a uniform high-power density light spot which is injected into the resonant cavity to excite the gain medium.

[0013] In a preferred embodiment of the present invention, the microfluidic chip includes a heat exchange chip, an air outlet chip and an air inlet chip; the heat exchange chip is used to control the flow of coolant in the flow, the air outlet chip is used to discharge the nitrogen in the focusing lens group, and the air inlet chip is used to control the nitrogen in the nitrogen tank to enter the focusing lens group.

[0014] In a preferred embodiment of the present invention, the adjustment system includes a detection unit, a temperature sensing unit, a processing unit and a control unit; the detection unit is used to detect the distance between the focusing lens groups, the temperature sensing unit is used to detect the temperature in the resonant cavity, the processing unit is provided with an adjustment formula obtained by fitting a number of actual data, and the control unit is used to control the operation of a number of microfluidic chips to adjust the distance between the focusing lenses.

[0015] In a preferred embodiment of the present invention, the specific adjustment method of the adjustment system is:

[0016] S1: The pump light source emits pump light, which is focused and shaped by the focusing lens and then injected into the lens group to excite the gain medium;

[0017] S2: The light excited by the gain medium is emitted through a semi-reflective lens to form a laser. The temperature sensing unit detects the temperature in the resonant cavity and transmits it to the processing unit for processing through the adjustment formula.

[0018] S3: The processing unit transmits the processing result to the control unit, and the control unit controls the air inlet chip and the air outlet chip and further controls the distance between the focusing lens, so that the focusing lens injects a high-power-density spot of the pump light model into the resonant cavity.

[0019] In a preferred embodiment of the present invention, the control unit can also control the operation of the heat exchange chip, thereby controlling the flow of the coolant, controlling the coolant to move to the resonance cavity to absorb heat, and then move to the focusing lens to perform heat exchange with nitrogen. At the same time, the air inlet chip and the air outlet chip control the inlet and outlet of nitrogen in the focusing lens.

[0020] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0021] (1) The present invention provides a compact high-power semiconductor pumped solid-state laser. By using an elliptical flow channel and a heat exchange chip in coordination with each other, a coolant is arranged in the elliptical flow channel. The flow channel flows through a coupling mechanism and the top of a resonant cavity. A plurality of elliptical flow channels are arranged at the top of a circumference of a radiation cavity. The lengths of the plurality of elliptical flow channels gradually decrease. Each flow channel is nested and controlled by a heat exchange chip. Compared with the prior art, the heat exchange chip is used to control the coolant to flow from the top of the resonant cavity to the top of a focusing lens group, thereby absorbing and releasing heat. This greatly reduces the situation in which, under high-power pumping, a large amount of heat is generated after the laser crystal absorbs the pump light, causing the crystal temperature to rise, thereby affecting the output performance and stability of the laser.

[0022] (2) The present invention provides a compact high-power semiconductor pumped solid-state laser. A connected microfluidic channel is opened on the radiation cavity between the nitrogen tank and the focusing lens group. The microfluidic channel is controlled by an air inlet chip. When needed, the air inlet chip absorbs the nitrogen in the nitrogen tank to between the first focusing lens and the second focusing lens. A heat exchange chip is also arranged in the flow channel. The heat exchange chip controls the flow of coolant in the flow channel. When the coolant flows to the top of the resonant cavity, the heat inside the resonant cavity is absorbed. The flow of coolant is continuously controlled. When the coolant flows to the top of the focusing lens group, the nitrogen absorbs heat. If the first focusing lens and the second focusing lens do not need to adjust the spacing, the air outlet chip controls the expanded nitrogen to flow to the outside. If the spacing needs to be adjusted, the air outlet chip is closed. In this way, the heat at the resonant cavity is reduced while the spacing between the focusing lens groups is adjusted, so that the focusing lens groups can be better coupled to form a high-power density light spot to excite the gain medium, thereby avoiding the situation where the distribution of the pump light in the crystal becomes uneven under high-power pumping, resulting in large differences in pumping efficiency in different regions of the crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a three-dimensional structural diagram of a preferred embodiment of the present invention;

[0025] In the figure: 1. stimulated radiation mechanism; 2. coupling mechanism; 3. adjustment mechanism; 4. radiation cavity; 5. pump light source; 6. focusing lens group; 7. nitrogen tank; 8. flow channel; 9. radiation cavity; 10 lens group; 11. gain medium. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "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, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, "multiple" means two or more.

[0029] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0030] As shown in the figure, a compact high-power semiconductor-pumped solid-state laser comprises: a stimulated radiation mechanism, a coupling mechanism arranged at one end of the stimulated radiation mechanism, and an adjustment mechanism arranged on the circumference of the stimulated radiation mechanism.

[0031] The stimulated radiation mechanism comprises: a radiation cavity, a lens group arranged inside the radiation cavity, and a gain medium arranged between the lens groups; a coupling mechanism is arranged at one end of the lens group, and a flow channel is opened inside the circumferential cavity wall of the radiation cavity;

[0032] In a preferred embodiment of the present invention, the lens group includes a semi-reflective lens and a total reflection lens, the gain medium is arranged in the middle position between the semi-reflective lens and the total reflection lens, and the semi-reflective lens and the total reflection lens form a resonant cavity.

[0033] In a preferred embodiment of the present invention, the coupling mechanism is disposed at one end close to the total reflection lens, and the light generated by the coupling mechanism can be incident from one side of the total reflection lens into the lens group to excite the gain medium.

[0034] In a preferred embodiment of the present invention, the radiation cavity is cylindrical, the flow channel is opened inside the radiation cavity, the flow channel is nested in a plurality of ellipses of different sizes, the flow channel is located on top of the lens group and the coupling mechanism, and a coolant is arranged in the flow channel.

[0035] It should be noted that the radiation cavity is arranged in a cylindrical shape, the lens group is arranged in the middle of the radiation cavity to form a resonant cavity, the gain medium is arranged inside the resonant cavity, the resonant cavity includes a total reflection lens and a half-reflection mirror, and the coupling mechanism is also arranged in the radiation cavity, but is arranged outside the resonant cavity, and is arranged near one end of the total reflection lens. A plurality of elliptical flow channels are arranged at the top of the circumference of the radiation cavity, and the lengths of the plurality of elliptical flow channels gradually decrease. Each flow channel is nested, and a coolant is provided in the flow channel, and the flow channel flows through the coupling mechanism and the top of the resonant cavity.

[0036] The coupling mechanism includes: a pump light source, and a focusing lens group arranged at one end of the pump light source; the focusing lens group is slidably connected with the radiation cavity, and the inner side of the focusing lens group is filled with nitrogen that can absorb heat and expand;

[0037] In a preferred embodiment of the present invention, the focusing lens group includes a first focusing lens and a second focusing lens, the first focusing lens is fixedly connected to the radiation cavity, the second focusing lens is slidably connected to the radiation cavity, and nitrogen is filled between the first focusing lens and the second focusing lens.

[0038] In a preferred embodiment of the present invention, the pump light source emits pump light which is focused and shaped by a focusing lens group to form a uniform high-power density light spot which is injected into the resonant cavity to excite the gain medium.

[0039] It should be noted that the pump light source is arranged at the outermost side in the radiation cavity, and a focusing lens group is also arranged between the pump light source and the resonant cavity. The focusing lens group includes a first focusing mirror and a second focusing mirror. The first focusing mirror is fixedly connected to the radiation cavity, and the second focusing mirror is slidably connected to the radiation cavity, that is, the second focusing lens can move back and forth in the radiation cavity, and the first focusing mirror and the second focusing mirror are both sealed inside the radiation cavity. Both are filled with nitrogen, which can absorb heat and expand after being heated. When in use, the pump light source emits pump light, which is coupled by the focusing lens group, passes through the total reflection lens and enters the resonant cavity, excites the gain medium, emits light, reflects in the resonant cavity, and emits laser.

[0040] The regulating mechanism comprises: a nitrogen tank threadedly connected to the radiation cavity; a gas storage cavity is arranged at the bottom in the middle of the focusing lens group, a plurality of microfluidic chips are arranged in the radiation cavity, and a regulating system is arranged in the microfluidic chip.

[0041] In a preferred embodiment of the present invention, the microfluidic chip includes a heat exchange chip, an air outlet chip and an air inlet chip; the heat exchange chip is used to control the flow of coolant in the flow, the air outlet chip is used to discharge the nitrogen in the focusing lens group, and the air inlet chip is used to control the nitrogen in the nitrogen tank to enter the focusing lens group.

[0042] In a preferred embodiment of the present invention, the adjustment system includes a detection unit, a temperature sensing unit, a processing unit and a control unit; the detection unit is used to detect the distance between the focusing lens groups, the temperature sensing unit is used to detect the temperature in the resonant cavity, the processing unit is provided with an adjustment formula obtained by fitting a number of actual data, and the control unit is used to control the operation of a number of microfluidic chips to adjust the distance between the focusing lenses.

[0043] It should be noted that the nitrogen tank is fixedly connected to the radiation cavity through a thread, and can be connected to the focusing lens group through an air intake chip. The control unit can control the air intake chip in the microfluidic chip to extract the nitrogen in the nitrogen tank and transport it to the first focusing lens and the second focusing lens. That is, a connected microfluidic channel is opened on the radiation cavity between the nitrogen tank and the focusing lens group, and an air intake chip is arranged in the middle of this microfluidic channel. When needed, the air intake chip absorbs the nitrogen in the nitrogen tank to between the first focusing lens and the second focusing lens. Similarly, a heat exchange chip is also arranged in the flow channel. The heat exchange chip controls the flow of the coolant in the flow channel. When the coolant flows to the top of the resonant cavity, it absorbs the heat inside the resonant cavity and continuously controls the flow of the coolant. When it flows to the top of the focusing lens group, the nitrogen absorbs heat. If the first focusing lens and the second focusing lens do not need to adjust the distance, the air outlet chip controls the expanded nitrogen to flow to the outside. If the distance needs to be adjusted, the air outlet chip is closed.

[0044] In a preferred embodiment of the present invention, the specific adjustment method of the adjustment system is:

[0045] S1: The pump light source emits pump light, which is focused and shaped by the focusing lens and then injected into the lens group to excite the gain medium;

[0046] S2: The light excited by the gain medium is emitted through a semi-reflective lens to form a laser. The temperature sensing unit detects the temperature in the resonant cavity and transmits it to the processing unit for processing through the adjustment formula.

[0047] S3: The processing unit transmits the processing result to the control unit, and the control unit controls the air inlet chip and the air outlet chip and further controls the distance between the focusing lens, so that the focusing lens injects a high-power-density spot of the pump light model into the resonant cavity.

[0048] In a preferred embodiment of the present invention, the control unit can also control the operation of the heat exchange chip, thereby controlling the flow of the coolant, controlling the coolant to move to the resonance cavity to absorb heat, and then move to the focusing lens to perform heat exchange with nitrogen. At the same time, the air inlet chip and the air outlet chip control the inlet and outlet of nitrogen in the focusing lens.

[0049] It should be noted that the adjustment formula is obtained through fitting, and is used to calculate the ratio of the heat generated by the crystal to the appropriate spacing between the lenses. Such a ratio will be affected by many factors, including but not limited to: The power of the pump light: The higher the pump light power, the more heat the crystal generates. The thermal conductivity of the crystal: The thermal conductivity determines the speed and efficiency of heat transfer inside the crystal. The efficiency of the coolant: The ability of the coolant to absorb and transfer heat will affect the stability of the crystal temperature and the adjustment of the lens spacing. The thermal expansion coefficient of the lens material: Lenses of different materials will have different expansion amounts under the same temperature change. The design of the resonant cavity: The structure and parameters of the resonant cavity will also affect the performance of the laser and the suitability of the lens spacing. The formula is obtained by constructing a model based on physical principles and fitting the parameters in the model through experimental data.

[0050] Q: heat generated by the crystal (unit: joule / second, i.e. watt); d: spacing between lenses (unit: meter); R: suitable spacing ratio (unitless, may be the ratio of d to a reference spacing); pump light power P, crystal thermal conductivity k, coolant efficiency η, β: thermal expansion coefficient of lens material (unit: 1 / Kelvin, 1 / K) ΔT: crystal temperature change (unit: Kelvin, K)

[0051] The heat generated by the crystal is proportional to the pump light power, that is, Q = αP, where α is the conversion efficiency; Assuming that the suitability of the lens spacing is related to the stability of the crystal temperature and the thermal expansion of the lens, a function related to the temperature difference ΔT and the lens thermal expansion coefficient β is introduced. Assuming that the heat generated by the crystal is proportional to the pump light power, that is, Q = αP, where α is the conversion efficiency, which depends on the crystal material and the wavelength of the pump light.

[0052] dopt==d0+βΔT·LR=d0dopt=1+d0βΔT·L;

[0053] Where d0 is the initial or reference spacing, L is the characteristic length of the lens or related structure (such as the diameter or focal length of the lens), and ΔT is the change in temperature due to heat.

[0054] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A compact high-power semiconductor-pumped solid-state laser, comprising: A stimulated radiation mechanism, a coupling mechanism arranged at one end of the stimulated radiation mechanism, and an adjustment mechanism arranged on the circumference of the stimulated radiation mechanism, characterized in that: The stimulated radiation mechanism comprises: a radiation cavity, a lens group arranged inside the radiation cavity, and a gain medium arranged between the lens groups; the coupling mechanism is arranged at one end of the lens group, and a flow channel is opened inside the circumferential cavity wall of the radiation cavity; The coupling mechanism comprises: a pump light source, and a focusing lens group arranged at one end of the pump light source; the focusing lens group is slidably connected to the radiation cavity, and the inner side of the focusing lens group is filled with nitrogen that can absorb heat and expand; The regulating mechanism comprises: a nitrogen tank threadedly connected to the radiation cavity; the gas storage cavity is arranged at the bottom in the middle of the focusing lens group, a plurality of microfluidic chips are arranged in the radiation cavity, and an regulating system is arranged in the microfluidic chip.

2. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The lens group includes a semi-reflective lens and a total reflection lens, the gain medium is arranged in the middle position between the semi-reflective lens and the total reflection lens, and the semi-reflective lens and the total reflection lens form a resonant cavity.

3. A compact high-power semiconductor-pumped solid-state laser according to claim 2, characterized in that: The coupling mechanism is arranged at one end close to the total reflection lens, and the light generated by the coupling mechanism can be injected into the lens group from one side of the total reflection lens to excite the gain medium.

4. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The radiation cavity is cylindrically arranged, the flow channel is opened inside the radiation cavity, the flow channel is nested in a plurality of ellipses of different sizes, the flow channel is located on top of the lens group and the coupling mechanism, and a coolant is arranged in the flow channel.

5. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The focusing lens group includes a first focusing lens and a second focusing lens, the first focusing lens is fixedly connected to the radiation cavity, the second focusing lens is slidably connected to the radiation cavity, and the nitrogen is filled between the first focusing lens and the second focusing lens.

6. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The pump light source emits pump light which is focused and shaped by the focusing mirror group to form a uniform high-power density light spot and is injected into the resonant cavity to excite the gain medium.

7. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The microfluidic chip includes a heat exchange chip, an air outlet chip and an air intake chip; the heat exchange chip is used to control the flow of coolant in the flow, the air outlet chip is used to discharge the nitrogen in the focusing lens group, and the air intake chip is used to control the nitrogen in the nitrogen tank to enter the focusing lens group.

8. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The adjustment system includes a detection unit, a temperature sensing unit, a processing unit and a control unit; the detection unit is used to detect the distance between the focusing lens groups, the temperature sensing unit is used to detect the temperature in the resonant cavity, the processing unit is provided with an adjustment formula obtained by fitting a number of actual data, and the control unit is used to control the operation of a number of microfluidic chips to adjust the distance between the focusing lenses.

9. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The specific adjustment method of the adjustment system is: S1: The pump light source emits pump light, which is focused and shaped by the focusing lens and then injected into the lens group to excite the gain medium; S2: The light excited by the gain medium is emitted through a semi-reflective lens to form a laser. The temperature sensing unit detects the temperature in the resonant cavity and transmits it to the processing unit for processing through the adjustment formula. S3: The processing unit transmits the processing result to the control unit, and the control unit controls the air inlet chip and the air outlet chip and further controls the distance between the focusing lens, so that the focusing lens injects a high-power-density spot of the pump light model into the resonant cavity.

10. A compact high-power semiconductor-pumped solid-state laser according to claim 1, characterized in that: The control unit can also control the operation of the heat exchange chip, thereby controlling the flow of the coolant, controlling the coolant to move to the resonance cavity to absorb heat, and then move to the focusing lens to exchange heat with nitrogen. At the same time, the air inlet chip and the air outlet chip control the inlet and outlet of the nitrogen in the focusing lens.

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