Lateral unidirectional pumping cavity of laser diode array

Abstract

The invention relates to the technical field of laser diodes, and provides a laser diode array side unidirectional pumping cavity comprising a pumping source used for emitting pumping light; the diffuse reflection cavity is arranged on one side of the pumping source, the inner side wall of the diffuse reflection cavity comprises a curved surface part and a straight inclined surface part, a gap is formed in the center line of the straight inclined surface part, and the gap serves as an incident port of the pumping light; the incident port is opposite to the light-emitting surface of the pumping source; the cooling pipe is arranged on the side, away from the pumping source, of the diffuse reflection cavity; the laser gain medium and the cooling pipe are coaxially arranged, the laser gain medium is located on the inner side of the cooling pipe, and the space between the laser gain medium and the cooling pipe is filled with cooling liquid. Through the arrangement of the curved surface part and the straight inclined surface part of the diffuse reflection cavity and the arrangement of the cooling pipe and the laser gain medium on the side, far away from the pumping source, of the diffuse reflection cavity, uniformization can be carried out on one-way pumping light entering the laser gain medium, and one-way high-power and high-uniformity pumping of the laser gain medium is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of laser diodes, and in particular to a side unidirectional pumping cavity of a laser diode array. Background Art

[0002] The laser diode array side pump cavity is the core element for obtaining high-power and high-beam-quality solid-state lasers.

[0003] In the prior art, many methods are used to improve pump power and pump uniformity, most of which are to improve pump power and pump uniformity by multi-directional side pumping, or to improve pump coupling to improve pump uniformity.

[0004] However, the use of a multi-directional pump structure or the addition of complex coupling elements makes the pump cavity structure more complicated, the installation and debugging are more difficult, and the cost is higher. Summary of the invention

[0005] The present invention provides a laser diode array side unidirectional pumping cavity, which is used to solve the defects in the prior art that the multi-directional pumping structure or the addition of complex coupling elements makes the pumping cavity structure complicated and the installation and debugging difficulty increased, and realizes unidirectional high-power and high-uniformity pumping of the laser gain medium.

[0006] The present invention provides a laser diode array side unidirectional pumping cavity, comprising:

[0007] A pump source, used for emitting pump light;

[0008] A diffuse reflection cavity, the inner side of which forms a diffuse reflection cavity; the diffuse reflection cavity is arranged on one side of the pump source, and the inner side wall of the diffuse reflection cavity includes a curved surface portion and a straight inclined surface portion, and a slit is opened at the center line of the straight inclined surface portion, and the slit serves as an incident port for the pump light; and the incident port is opposite to the light-emitting surface of the pump source;

[0009] A cooling tube, arranged on a side of the diffuse reflection cavity away from the pump source;

[0010] The laser gain medium is coaxially arranged with the cooling tube and located inside the cooling tube, and a cooling liquid is filled between the laser gain medium and the cooling tube.

[0011] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the axis of the cooling tube is arranged parallel to the extension direction of the gap.

[0012] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the cross-section of the curved surface portion in the radial direction of the cooling tube is partially elliptical.

[0013] A laser diode array side unidirectional pumping cavity provided according to the present invention also includes a pump source heat sink, which is arranged at the bottom of the pump source and the diffuse reflection cavity, and the pump source heat sink is used to provide heat dissipation for the pump source and the diffuse reflection cavity.

[0014] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the diameter of the laser gain medium is less than 3 mm, and the curved portion is a U-shaped cross-section in the radial direction of the cooling tube.

[0015] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the pumping source is a laser diode array, and the power of a single laser diode in the laser diode array is greater than 100W.

[0016] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the length of the gap is the same as the width of the laser diode array.

[0017] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the diffuse reflection cavity is made of alumina ceramics, polytetrafluoroethylene, magnesium oxide powder and barium sulfate powder.

[0018] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the pumping light, the gap, the cooling tube and the laser gain medium are all located on the center line of the diffuse reflection cavity.

[0019] According to a laser diode array side unidirectional pumping cavity provided by the present invention, the cooling tube is a quartz glass tube.

[0020] The laser diode array side unidirectional pump cavity provided by the present invention emits pump light through a pump source, and a diffuse reflection cavity is formed inside the diffuse reflection cavity. The diffuse reflection cavity is arranged on one side of the pump source, and the inner side wall of the diffuse reflection cavity includes a curved surface and a straight inclined surface. A gap is opened at the center line of the straight inclined surface, and the gap serves as an incident port for the pump light, which is opposite to the light-emitting surface of the pump source. The laser gain medium and the cooling tube are coaxially arranged, and the two are located on the side of the diffuse reflection cavity away from the pump source. Through the arrangement of the reflection cavity, the unidirectional pump light incident on the laser gain medium is homogenized, so as to realize unidirectional high-power and high-uniformity pumping of the laser gain medium.

[0021] Moreover, the laser diode array side unidirectional pumping cavity provided by the present invention adopts a unidirectional pumping structure, which does not require complex coupling elements compared to a multidirectional pumping structure, making the side pumping structure simpler, more convenient to install and debug, and lower in cost.

[0022] In addition, compared with the unidirectional pumping structure in the prior art, in which the laser gain medium in the prior art is at an equal distance from the inner side wall of the diffuse reflection cavity, the inner side wall of the diffuse reflection cavity of the present invention includes a curved surface and a straight inclined surface, and a slit is provided at the center line of the straight inclined surface, and the slit serves as the incident port of the pump light, and is opposite to the light-emitting surface of the pump source, and the laser gain medium and the cooling tube are coaxially arranged, and the two are located on the side of the diffuse reflection cavity away from the pump source, and the distance between the pump source and the laser gain medium is lengthened, which can realize multiple reflections of the pump source in the diffuse reflection cavity, so that the laser gain medium can realize high-uniformity pumping. At the same time, since the distance between the pump source and the laser gain medium is lengthened, a relatively high-power laser diode can also be used, and the normal use of the laser gain medium can also be guaranteed, that is, unidirectional high-power pumping of the laser gain medium is realized. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 1 It is a schematic diagram of the structure of the unidirectional pumping cavity on the side of the laser diode array provided by the present invention;

[0025] Figure 2 It is a side view of the unidirectional pumping cavity on the side of the laser diode array provided by the present invention;

[0026] Figure 3 It is a schematic diagram of the diffuse reflection cavity structure in the unidirectional pumping cavity on the side of the laser diode array provided by the present invention;

[0027] Figure 4 It is the simulation result of the pump uniformity in the crystal when the diameter of the laser gain medium provided by the present invention is 3 mm;

[0028] Figure 5 It is another structural schematic diagram of the side unidirectional pumping cavity of the laser diode array provided by the present invention;

[0029] Figure 6 It is a side view of the unidirectional pumping cavity on the side of the laser diode array provided by the present invention;

[0030] Figure 7 is a schematic structural diagram of another diffuse reflection cavity provided by the present invention;

[0031] Figure 8 This is the simulation result of the pump uniformity in the crystal when the diameter of the laser gain medium provided by the present invention is 2.5 mm.

[0032] Reference numerals:

[0033] 1. Pump source; 2. Diffuse reflection cavity; 21. Curved surface; 22. Straight inclined surface; 3. Gap; 4. Cooling tube; 5. Laser gain medium; 6. Pump source heat sink. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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.

[0035] In the description of the embodiments of the present invention, it should be noted 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 embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0036] In the prior art, in order to improve the pump power and pump uniformity, multi-directional side pumping is usually used to improve the pump power and pump uniformity, or the pump coupling method is improved to improve the pump uniformity. However, due to the use of multi-directional pumping structure or the addition of complex coupling elements, the pump cavity structure is complicated, the installation and debugging are more difficult, and the cost is high.

[0037] In the unidirectional pumping method of the prior art, since the inner wall of the diffuse reflection cavity is at an equal distance from the laser gain medium, not only the side of the laser gain medium close to the pump source directly receives the incident pump light, resulting in uneven pumping, but also, due to the short distance, in order to ensure the effective use of the laser gain medium, the power of the pump source is usually 40-60W to prevent damage to the laser gain medium.

[0038] Combine the following Figures 1 to 8 The laser diode array side unidirectional pumping cavity of the present invention is described.

[0039] like Figure 1 As shown, the present invention provides a laser diode array side unidirectional pumping cavity, including a pump source 1, a diffuse reflection cavity 2, a cooling tube 4 and a laser gain medium 5.

[0040] Among them, Figure 2 As shown, the pump source 1 is used to emit pump light; a diffuse reflection cavity is formed on the inner side of the diffuse reflection cavity 2; the diffuse reflection cavity 2 is arranged on one side of the pump source 1, and the inner wall of the diffuse reflection cavity 2 includes a curved surface 21 and a straight inclined surface 22, and a gap 3 is opened at the center line of the straight inclined surface, and the gap 3 serves as an incident port for the pump light; and the incident port is opposite to the light-emitting surface of the pump source 1; a cooling tube 4 is arranged on the side of the diffuse reflection cavity away from the pump source 1; a laser gain medium 5 is coaxially arranged with the cooling tube 4 and is located on the inner side of the cooling tube 4, and a coolant is filled between the laser gain medium 5 and the cooling tube 4.

[0041] Among them, the laser gain medium 5 can be made of laser crystals such as Nd:YAG (Neodymium-dopedYttrium Aluminum Garnet; or yttrium aluminum garnet crystal in Chinese), Nd:YLF, Nd:glass, Yb:YAG, Tm:YAG, Tm:YAP, Tm:Ho:YAG, Tm:YLF, Nd:YVO4, Er:YAG, Er:YSGG, etc.

[0042] The embodiment of the present invention homogenizes the unidirectional pump light incident on the laser gain medium 5 by setting up the diffuse reflection cavity 2, thereby realizing unidirectional high-power and high-uniformity pumping of the laser gain medium 5; the unidirectional pumping structure does not require complex coupling elements compared to the multi-directional pumping structure, making the side pumping structure simpler, more convenient to install and debug, and lower in cost.

[0043] In addition, compared with the unidirectional pumping structure in the prior art, in which the laser gain medium is at an equal distance from the inner side wall of the diffuse reflection cavity 2, the inner side wall of the diffuse reflection cavity 2 of the present invention includes a curved surface 21 and a straight bevel surface 22, and a slit is provided at the center line of the straight bevel surface 22, which serves as an incident port for pump light and is opposite to the light-emitting surface of the pump source 1, and the laser gain medium 5 and the cooling tube 4 are coaxially arranged, and both are located on the side of the diffuse reflection cavity away from the pump source 1, and the distance between the pump source 1 and the laser gain medium 5 is lengthened, which can realize multiple reflections of the pump source 1 in the diffuse reflection cavity 2, so that the laser gain medium 5 can realize high-uniform pumping, so that the laser spot effect generated in the laser gain medium 5 is better. At the same time, since the distance between the pump source 1 and the laser gain medium 5 is lengthened, a relatively high-power pump source 1 can be used, and the normal use of the laser gain medium 5 can be guaranteed, that is, unidirectional high-power pumping of the laser gain medium 5 is realized.

[0044] In a feasible embodiment of the present invention, the axis of the cooling tube 4 is arranged parallel to the extension direction of the gap 3, so that the laser gain medium 5 located inside the cooling tube 4 can be cooled in a microchannel or macrochannel manner.

[0045] In a feasible embodiment of the present invention, the cross section of the curved surface 21 in the radial direction of the cooling tube 4 is a partial ellipse. The axes of the cooling tube 4 and the laser gain medium 5 are located on the major axis of the ellipse, and the axis and the major axis of the ellipse are perpendicular to each other.

[0046] like Figure 3 and Figure 4 As shown, the pump uniformity in the laser gain medium 5 was simulated.

[0047] The simulation conditions are:

[0048] (1) The wavelength of the pump light emitted by the laser diode array is 808 nm, and the fast axis divergence angle of the pump light is 70°;

[0049] (2) The laser gain medium is Nd:YAG crystal with a diameter of 3 mm and a doping concentration of 0.6% at;

[0050] (3) The inner diameter of the cooling tube 4 is 4 mm and the outer diameter is 6 mm;

[0051] (4) The liquid flowing between the laser gain medium 5 and the cooling tube 4 is water.

[0052] Under the above conditions, the structure of the diffuse reflection cavity 4 is optimized by optimizing the major axis a, minor axis b, distance c from the center of the ellipsoid to the inclined surface, distance d between the laser gain medium 5 and the center of the ellipsoid, and inclination angle θ of the straight inclined surface.

[0053] The results are as follows Figure 4 As shown, the pump light distribution is relatively uniform within the range of the central diameter of the Nd:YAG crystal less than 2 mm.

[0054] In a feasible embodiment of the present invention, a pump source heat sink 6 is further included, which is arranged at the bottom of the pump source 1 and the diffuse reflection cavity 2. The pump source heat sink 6 is used to provide heat dissipation for the pump source 1 and the diffuse reflection cavity 2, and the pump source heat sink 6 is used to fix the pump source 1 and the diffuse reflection cavity 2.

[0055] like Figure 5-Figure 8 As shown, in a feasible embodiment of the present invention, the diameter of the laser gain medium 5 is less than 3 mm, and the cross-section of the curved portion 21 in the radial direction of the cooling tube 4 is U-shaped.

[0056] like Figure 5 and Figure 6 As shown, based on the diffuse reflection cavity 2 of the U-shaped structure in this embodiment, the pump uniformity in the laser gain medium is simulated.

[0057] The simulation conditions are:

[0058] (1) The wavelength of the pump light emitted by the laser diode array is 808 nm, and the fast axis divergence angle of the pump light is 70°;

[0059] (2) The laser gain medium 5 is a Nd:YAG crystal with a diameter of 3 mm and a doping concentration of 0.6% at;

[0060] (3) The inner diameter of the cooling tube 4 is 4 mm and the outer diameter is 6 mm;

[0061] (4) The liquid flowing between the laser gain medium 5 and the cooling tube 4 is water.

[0062] like Figure 7 As shown, under the above conditions, the structure of the diffuse reflection cavity 2 is optimized, and the pump light is distributed more evenly in the laser crystal by optimizing the curvature radius R of the U-shaped structure, the distance a from the center of the arc surface to the inclined surface in the U-shaped structure, the width b of the U-shaped structure, the distance c between the laser gain medium 5 and the straight inclined surface, and the inclination angle θ of the straight inclined surface.

[0063] The results are as follows Figure 8 As shown, the pump light distribution is relatively uniform within the range of the central diameter of the Nd:YAG crystal less than 1.5 mm.

[0064] In a feasible embodiment of the present invention, the pump source 1 is a laser diode array, which can be a horizontal array composed of a single diode or more than two diodes, and the pumping method can be continuous light or pulsed light. And the power of a single laser diode in the laser diode array is greater than 100W. Single-channel pump light injection pumping is adopted, and a high-power laser diode is used as a pump source to inject the laser gain medium 5, which meets the requirements of the solid laser gain medium to reach an excited state, can simplify the complexity of the equipment, thereby effectively reducing the complexity of the equipment, facilitating installation and easier maintenance.

[0065] In a feasible embodiment of the present invention, the length of the slit 3 is the same as the width of the laser diode array, so that the pump light emitted by the laser diode can fully enter the diffuse reflection cavity through the slit 3. In addition, the width of the slit 3 can be set to 1 mm, and the depth can be set to 1 mm.

[0066] In a feasible embodiment of the present invention, the diffuse reflection cavity 2 is made of alumina ceramics, polytetrafluoroethylene, magnesium oxide powder, and barium sulfate powder.

[0067] In a feasible embodiment of the present invention, the pump light, the gap 3, the cooling tube 4 and the laser gain medium 5 are all located on the center line of the diffuse reflection cavity 2, so that the entire diffuse reflection cavity 2 forms a symmetrical structure, thereby making the pump light have better uniformity.

[0068] In a feasible embodiment of the present invention, the cooling tube 4 is a quartz glass tube, and other materials with good light transmittance can also be used as long as good light transmittance can be achieved under the condition of ensuring a certain mechanical strength.

[0069] In summary, the laser diode side unidirectional pumping cavity provided by the present invention can realize unidirectional high-power and high-uniformity pumping of the laser gain medium. Compared with the prior art, it can realize unidirectional higher-power pumping of the laser gain medium 5 while having better uniformity. In addition, the unidirectional pumping structure is adopted, and no complex coupling elements are required, so that the side pumping cavity structure is simpler, and installation and debugging are more convenient, and the cost is lower.

[0070] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0071] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0072] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" 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 a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser diode array side unidirectional pumping cavity, characterized in that: include: A pump source (1) for emitting pump light; A diffuse reflection cavity (2) having a diffuse reflection cavity formed inside; the diffuse reflection cavity (2) is arranged on one side of the pump source (1), and the inner side wall of the diffuse reflection cavity (2) comprises a curved surface portion (21) and a straight inclined surface portion (22), and a slit (3) is provided at the center line of the straight inclined surface portion, and the slit (3) serves as an incident port for pump light; and the incident port is opposite to the light-emitting surface of the pump source (1); A cooling tube (4) is arranged on a side of the diffuse reflection cavity away from the pump source (1); The laser gain medium (5) is coaxially arranged with the cooling tube (4) and is located inside the cooling tube (4), and a cooling liquid is filled between the laser gain medium (5) and the cooling tube (4).

2. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The axis of the cooling pipe (4) is arranged parallel to the extension direction of the slit (3).

3. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The cross section of the curved surface portion (21) in the radial direction of the cooling pipe (4) is partially elliptical.

4. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: It also comprises a pump source heat sink (6) which is arranged at the bottom of the pump source (1) and the diffuse reflection cavity (2), and the pump source heat sink (6) is used to provide heat dissipation for the pump source (1) and the diffuse reflection cavity (2).

5. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The diameter of the laser gain medium (5) is less than 3 mm, and the cross-section of the curved surface portion (21) in the radial direction of the cooling tube (4) is U-shaped.

6. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The pump source (1) is a laser diode array, and the power of a single laser diode in the laser diode array is greater than 100W.

7. The laser diode array side unidirectional pumping cavity according to claim 6, characterized in that: The length of the slit (3) is the same as the width of the laser diode array.

8. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The diffuse reflection cavity (2) is made of alumina ceramics, polytetrafluoroethylene, magnesium oxide powder and barium sulfate powder.

9. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The pump light, the gap (3), the cooling tube (4) and the laser gain medium (5) are all located on the center line of the diffuse reflection cavity (2).

10. The laser diode array side unidirectional pumping cavity according to claim 1, characterized in that: The cooling tube (4) is a quartz glass tube.

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