External resonator laser module

Abstract

An external resonance type laser module includes a quantum cascade laser element, a MEMS diffraction grating, a support plate having a first surface on which the quantum cascade laser element and the MEMS diffraction grating are arranged and a second surface opposite to the first surface, and a cooling element arranged on the second surface of the support plate so as to overlap the quantum cascade laser element and the MEMS diffraction grating. In the second surface of the support plate, at least a region overlapping the quantum cascade laser element and the MEMS diffraction grating when viewed in a thickness direction is provided with a recessed portion recessed in a direction from the second surface toward the first surface. At least a portion of the support plate on the side of the cooling element is inserted into the recessed portion.

Description

Technical Field

[0001] This invention relates to an external resonant laser module. Background Technology

[0002] As a light source for wavelength scanning, an external resonant laser module is known (see, for example, Patent Document 1) that includes a quantum cascade laser element (hereinafter referred to as "QCL element") and a diffraction grating that diffracts and reflects the light emitted from the QCL element. In Patent Document 1, a structure is disclosed in which the QCL element and the diffraction grating are arranged on the main surface of a support plate, and a Peltier element as a cooling element is arranged on the back side of the support plate.

[0003] Existing technical documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-036577 Summary of the Invention

[0005] The problem that the invention aims to solve

[0006] Compared to other laser light sources such as laser diodes, QCL elements generate more heat, thus requiring high cooling performance for external resonant laser modules equipped with QCL elements. In the structure disclosed in Patent Document 1, the module is cooled by a Peltier element positioned on the opposite side of the QCL element and the diffraction grating, sandwiched between a support plate. Here, to achieve better cooling performance, the support plate is made as thin as possible. However, the inventors have discovered the following problem with this solution: simply thinning the support plate compromises its physical stability, potentially causing misalignment in the positional relationship between the QCL element and the diffraction grating. This could lead to a deterioration in the optical properties of the external resonant laser module.

[0007] Therefore, one aspect of the present invention is to provide an external resonant laser module that can suppress the deterioration of optical properties and improve the cooling effect.

[0008] Technical means to solve the problem

[0009] An external resonant laser module according to one aspect of the present invention comprises: a quantum cascade laser element; a diffraction grating that diffracts and reflects a portion of the light emitted from the quantum cascade laser element and returns it to the quantum cascade laser element; a support plate having a first surface on which the quantum cascade laser element and the diffraction grating are disposed and a second surface opposite to the first surface; and a cooling element disposed on the second surface of the support plate in such a way that it overlaps with the quantum cascade laser element and the diffraction grating when viewed from the thickness direction of the support plate. In the second surface of the support plate, in a region that overlaps at least with the quantum cascade laser element and the diffraction grating when viewed from the thickness direction of the support plate, a recess is provided in a direction from the second surface toward the first surface, and at least a portion of the cooling element on the support plate side is inserted into the recess.

[0010] In the aforementioned external resonant laser module, a recess is provided in the region overlapping the quantum cascade laser element and diffraction grating on the second surface of the support plate (the surface opposite to the first surface where the quantum cascade laser element and diffraction grating are arranged). A cooling element is then inserted into this recess. This structure shortens the distance between the quantum cascade laser element and the cooling element compared to a support plate without a recess. This improves the cooling effect based on the cooling element. Furthermore, the portion of the support plate without a recess ensures sufficient thickness to maintain the strength of the support plate. This improves the physical stability of the support plate compared to a uniformly thinned plate. Therefore, the deterioration of the optical properties of the external resonant laser module can be suppressed.

[0011] Viewed from the thickness direction of the support plate, at least a portion of the inner surface of the recess in the support plate can also contact at least a portion of the outer edge of the cooling element. In this case, since the cooling element can be positioned through the recess, product-to-product deviations in the configuration of the cooling elements can be prevented. This allows for stable cooling performance based on the cooling element.

[0012] The diffraction grating can have a diffraction reflector that diffracts and reflects a portion of the light emitted from the quantum cascade laser element, or it can cause a portion of the light to return to the quantum cascade laser element by shaking the diffraction reflector. In this case, in a Littrow-type external resonant laser module where the diffraction grating and the movable mechanism are integrated, the deterioration of optical properties can be suppressed and the cooling effect can be improved.

[0013] Alternatively, the circuit board for controlling the operation of the quantum cascade laser element may not be disposed on the opposite side of the support plate in the cooling element. In this case, by omitting the circuit board, which serves as a heat source, on the opposite side of the support plate in the cooling element, obstruction of heat dissipation from the cooling element can be prevented. This further improves the cooling effect based on the cooling element.

[0014] An auxiliary cooling element can also be configured on the opposite side of the support plate in the cooling element to further cool the cooling element. In this case, the cooling effect can be further improved by the auxiliary cooling element.

[0015] The aforementioned external resonant laser module can further include: multiple pillars erected on the first surface of a support plate and extending along the thickness direction of the support plate; and pillar connecting components disposed in the thickness direction of the support plate at a position further away from the support plate than the quantum cascade laser element, and connected to the ends of the multiple pillars. According to the above structure, the support plate is appropriately supported by the multiple pillars and pillar connecting components, thus further improving the physical stability of the support plate. Therefore, the deterioration of the optical properties of the external resonant structure module can be more effectively suppressed.

[0016] The aforementioned external resonant laser module may further include: a plurality of first pillars, erected on the first surface of a support plate and extending along the thickness direction of the support plate; and a first circuit board, disposed in the thickness direction of the support plate at a position further away from the support plate than the quantum cascade laser element, and connected to the ends of the plurality of first pillars. The first circuit board may also be a circuit board for controlling the operation of the quantum cascade laser element. Assuming the first circuit board is in contact with a cooling element, heat generated from the first circuit board may be transferred to the quantum cascade laser element via the cooling element and the support plate. Alternatively, heat generated from the first circuit board may hinder heat dissipation from the cooling element. On the other hand, according to the structure described above where the first circuit board is supported by a plurality of first pillars, by distributing the first circuit board, which is a heat source, at a position far from the cooling element, the aforementioned problems can be avoided. Furthermore, as described above, the physical stability of the support plate can be improved. That is, the first circuit board can function as a connecting member for the aforementioned pillars.

[0017] The aforementioned external resonant laser module may further include a noise filter circuit that receives a power signal from an external power source, removes noise contained in the power signal, and outputs the noise-removed power signal to the first circuit board. According to this structure, since the noise superimposed on the power signal is removed by the noise filter circuit, damage to the first circuit board caused by electrostatic surges, etc., can be prevented.

[0018] The aforementioned external resonant laser module may further include: a plurality of second pillars, erected on the first surface of a support plate and extending along the thickness direction of the support plate; and a second circuit board, disposed in the thickness direction of the support plate between the quantum cascade laser element and the first circuit board, and connected to the ends of each of the plurality of second pillars. The first circuit board may also have a higher heat dissipation than the second circuit board. According to the above structure, since the heat generated from the first circuit board is shielded by the second circuit board, heat transfer from the first circuit board to the quantum cascade laser element can be suppressed.

[0019] Viewed from the thickness direction of the support plate, the second circuit board can also overlap with at least a portion of the quantum cascade laser element and at least a portion of the first circuit board. According to the above structure, heat transfer from the first circuit board to the quantum cascade laser element can be more effectively suppressed.

[0020] The second circuit board can also be a circuit board with a noise filter circuit installed. The noise filter circuit can also receive a power signal from an external power source, remove noise contained in the power signal, and output the noise-removed power signal to the first circuit board. According to the above structure, by making the board with the noise filter circuit installed function as a second circuit board to shield the heat generated from the first circuit board, the miniaturization of the device can be achieved.

[0021] The aforementioned external resonant laser module can also be further equipped with a heat-conducting sheet disposed within a recess of the support plate, between the support plate and the cooling element. According to this structure, the cooling effect can be further improved because the heat transfer between the support plate and the cooling element can be enhanced.

[0022] The aforementioned external resonant laser module may further include: a base plate disposed on the opposite side of the support plate side of the cooling element, and a recess on the cooling element side of the base plate that is inserted into at least a portion of the base plate side of the cooling element. According to the above structure, the cooling element can be easily disposed relative to the base plate by providing the recess in the base plate.

[0023] The effects of the invention

[0024] According to one aspect of the present invention, an external resonant laser module that can suppress the deterioration of optical properties and improve the cooling effect can be provided. Attached Figure Description

[0025] Figure 1 This is a structural diagram of an analysis device including an external resonant laser module in one embodiment.

[0026] Figure 2 This is a cross-sectional view of an external resonant laser module.

[0027] Figure 3 It is along Figure 2 A cross-sectional view of line III-III. Detailed Implementation

[0028] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the following description, the same or equivalent elements will be referred to by the same reference numerals, and repeated descriptions will be omitted.

[0029] [Structure of the analytical device]

[0030] like Figure 1 As shown, the analysis apparatus 1 includes an external resonant laser module 2 (hereinafter referred to as "laser module 2"), a photodetector 3, and a control device 4. The analysis apparatus 1 is used for spectroscopic analysis by measuring the absorption spectrum. The analysis apparatus 1 is used, for example, with the analyte contained within a light-transmitting container, positioned between the laser module 2 and the photodetector 3. The analyte can be any of a gas, liquid, or solid. Alternatively, the analyte may not be contained within a container.

[0031] Laser module 2 is a wavelength-variable light source with a variable output light L. When measuring the absorption spectrum, laser module 2 performs wavelength scanning within a specified wavelength range by rapidly changing the wavelength of the output light L. Photodetector 3 detects the intensity of the output light L (or light reflected or scattered at the analyte) output from laser module 2 that has passed through it. Examples of photodetectors 3 include MCT (mercury cadmium telluride) detectors, InAsSb (indium antimony arsenide) photodiodes, and thermopile detectors. Control device 4 calculates the absorption spectrum based on the detection results from photodetector 3. Control device 4 is electrically connected to laser module 2 and photodetector 3. A detailed description of control device 4 follows.

[0032] [Structure of an external resonant laser module]

[0033] Reference Figure 2 and Figure 3 The structure of laser module 2 will be explained. Furthermore, in... Figure 3 The top and side walls of shell 5 are omitted from the illustration. Figure 2 and Figure 3As shown, the laser module 2 includes a housing 5, a support component 6, a cooling element 7, a heat sink 8, lenses 9A and 9B, a quantum cascade laser 11 (hereinafter referred to as "QCL 11"), a MEMS diffraction grating 12, a first circuit board 31, a second circuit board 32, an auxiliary cooling element 33, a plurality of (four in this embodiment) pillars B1 (first pillars), and a plurality of (two in this embodiment) pillars B2 (second pillars).

[0034] The housing 5 houses the support member 6, cooling element 7, heat sink 8, lenses 9A and 9B, QCL 11, MEMS diffraction grating 12, first circuit board 31, second circuit board 32, multiple supports B1, and multiple supports B2. The housing 5 is, for example, box-shaped and has a window 5a for outputting the output light L of the laser module 2 to the outside. Furthermore, the housing 5 is provided with a lead-out portion 5b for leading wiring, etc., to the outside. As an example, the length of each side of the housing 5 is approximately 70 mm. The housing 5 has a bottom wall 51 (base plate) for fixing the support member 6 via screws.

[0035] The support member 6 is formed, for example, of a metallic material with good thermal conductivity. The support member 6 is made, for example, of aluminum (Al). The support member 6 has a flat support plate 61 and a wall portion 62 erected on the support plate 61. The support member 6 is fixed to the bottom wall 51 of the housing 5 via a cooling element 7.

[0036] The support plate 61 functions as an optical stage in which the QCL 11, MEMS diffraction grating 12, and other optical elements (such as lenses 9A, 9B, etc.) are arranged. The support plate 61 has a first surface 61a in which the QCL 11 and MEMS diffraction grating 12 are arranged, and a second surface 61b opposite to the first surface 61a. As an example, the support plate 61 is circular when viewed from above (when viewed from the thickness direction D of the support plate 61). That is, the support plate 61 is a circular plate-shaped component. The support plate 61 is fixed to the bottom wall 51 by four screws S arranged at 90-degree intervals along the outer edge of the support plate 61.

[0037] In the second surface 61b of the support plate 61, a recess 61c (counterfeit hole) is provided in the region that overlaps at least with the quantum cascade laser element 13 (hereinafter referred to as "QCL element 13") and the MEMS diffraction grating 12 when viewed from the thickness direction D. As an example, the recess 61c, when viewed from the thickness direction D, is formed as a rectangular region including the heat sink 8 on which the QCL element 13 is mounted and the wall portion 62 on which the MEMS diffraction grating 12 is mounted. From the viewpoint of ensuring the strength of the support plate 61, the thickness t of the support plate 61 (i.e., the thickness of the portion where the recess 61c is not formed) is, for example, about 2 mm to 8 mm. The ratio (d / t) of the depth d of the recess 61c to the thickness t of the support plate 61 is, for example, about 10% to 50%.

[0038] The wall portion 62 has an inclined surface 62a that is tilted relative to the support plate 61. The MEMS diffraction grating 12 is fixed on the inclined surface 62a. The structure of the MEMS diffraction grating 12 will be described next.

[0039] The cooling element 7 is, for example, a cooling device comprising a Peltier element. As described above, the cooling element 7 is clamped between the support plate 61 and the bottom wall 51 by screws fixing the support plate 61 relative to the bottom wall 51. The cooling element 7 has a first substrate 71, a second substrate 72, and a heat-moving portion 73. The first substrate 71 is a flat plate component that is thermally coupled to the second surface 61b of the support plate 61. The second substrate 72 is a flat plate component similar to the first substrate 71 and is thermally coupled to the bottom wall 51 of the housing 5. The heat-moving portion 73 is disposed between the first substrate 71 and the second substrate 72, allowing heat to move between the first substrate 71 and the second substrate 72.

[0040] The cooling element 7 is arranged on the second surface 61b side of the support plate 61, overlapping the QCL element 13 and the MEMS diffraction grating 12 when viewed from the thickness direction D. At least a portion of the support plate 61 side of the cooling element 7 (i.e., at least a portion of the support plate 61 side of the first substrate 71) is inserted into the recess 61c. In this embodiment, when viewed from the thickness direction D, at least a portion of the inner surface of the recess 61c contacts at least a portion of the outer edge of the cooling element 7. As an example, the first substrate 71 of the cooling element 7 has a rectangle corresponding to the recess 61c when viewed from top (when viewed from the thickness direction D). Thus, at least a portion of the support plate 61 side of the cooling element 7 is embedded in the recess 61c. A heat-conducting sheet 34 is disposed between the support plate 61 and the cooling element 7 (first substrate 71) within the recess 61c. The heat-conducting sheet 34 is, for example, a graphite sheet. The thickness of the heat-conducting sheet 34 is, for example, about a few μm to tens of μm. Furthermore, the size of the cooling element 7 (the first substrate 71 in this embodiment) does not necessarily have to match the size of the recess 61c. That is, the cooling element 7 (the first substrate 71) can be formed to a size that allows it to be inserted into the recess 61c. For example, the cooling element 7 (the first substrate 71) can also be slightly smaller than the recess 61c. However, when the size of the cooling element 7 (the first substrate 71) matches the size of the recess 61c, the cooling element 7 can be easily positioned within the recess 61c.

[0041] A recess 51b is provided on the surface 51a of the bottom wall 51 of the housing 5 on the side of the cooling element 7. At least a portion of the bottom wall 51 side of the cooling element 7 (i.e., at least a portion of the bottom wall 51 side of the second substrate 72) is inserted into the recess 51b. In this embodiment, the recess 51b has a rectangle corresponding to the second substrate 72 when viewed from above (when viewed from the thickness direction D). Thus, at least a portion of the bottom wall 51 side of the cooling element 7 is embedded in the recess 51b. Furthermore, a heat-conducting sheet, the same as the heat-conducting sheet 34, may also be disposed between the bottom wall 51 and the cooling element 7 (second substrate 72) in the recess 51b. Furthermore, the size of the cooling element 7 (second substrate 72 in this embodiment) does not necessarily have to be the same as (correspond to) the size of the recess 51b. That is, the cooling element 7 (second substrate 72) can be formed to a size that can be inserted into the recess 51b. For example, the cooling element 7 (second substrate 72) may also be slightly smaller than the recess 51b. However, if the size of the cooling element 7 (second substrate 72) is consistent with the size of the recess 51b, the cooling element 7 can be easily positioned in the recess 51b.

[0042] In this embodiment, a circuit board for controlling the operation of the QCL element 13 is not disposed on the side opposite to the support plate 61 side of the cooling element 7 (i.e., the side opposite to where the bottom wall 51 is disposed on the cooling element 7). More specifically, the aforementioned circuit board is not disposed inside or outside the bottom wall 51. This ensures space for arranging additional cooling elements for further cooling the cooling element 7. Furthermore, an auxiliary cooling element 33 for further cooling the cooling element 7 is disposed on the side opposite to the support plate 61 side of the cooling element 7 (in this embodiment, the outer surface 51c of the bottom wall 51). The auxiliary cooling element 33 is, for example, a cooling device such as a water-cooled cooler or an air-cooled fan. The auxiliary cooling element 33 is thermally coupled to the outer surface 51c of the bottom wall 51. This allows heat to be released from the cooling element 7 to the auxiliary cooling element 33 via the bottom wall 51.

[0043] QCL 11 has a QCL element 13. The QCL element 13 has a first end face 13a and a second end face 13b facing each other. The QCL element 13 emits a wide band of light (e.g., 4 μm to 16 μm) in the mid-infrared region from the first end face 13a and the second end face 13b, respectively. The QCL element 13 has a structure in which multiple active layers with different center wavelengths are stacked, enabling the emission of such a wide band of light. Alternatively, the QCL element 13 may also have a structure consisting of a single active layer, in which case it can also emit such a wide band of light.

[0044] A reflection reduction section 14 is provided on the first end face 13a of the QCL element 13. The reflection reduction section 14 is, for example, composed of an AR (Anti-Reflection) layer with a reflectivity of less than 0.5%. The reflection reduction section 14 reduces the reflectivity of light emitted from the first end face 13a of the QCL element 13 to the outside, and also reduces the reflectivity of light incident from the outside onto the first end face 13a of the QCL element 13.

[0045] A reflection reduction section 15 is provided on the second end face 13b of the QCL element 13. The reflection reduction section 15 is, for example, composed of an AR layer with a reflectivity in the range of 0.6% to 10%. The reflection reduction section 15 reduces the reflectivity of light emitted from the second end face 13b of the QCL element 13 to the outside. The reflection reduction section 15 reflects a portion of the light emitted from the second end face 13b of the QCL element 13, allowing the remaining portion to pass through. The light that passes through the reflection reduction section 15 becomes the output light L of the QCL 11. Alternatively, the reflection reduction section 15 may not be provided on the second end face 13b. That is, the second end face 13b may be exposed.

[0046] The QCL 11 is secured to the support member 6 via a sub-mount bracket 16 and a heat sink 8. More specifically, a heat sink 8 is fixed to the first surface 61a of the support plate 61, and a sub-mount bracket 16 is fixed to the heat sink 8. The QCL 11 is secured to the sub-mount bracket 16. The sub-mount bracket 16 is, for example, a ceramic substrate containing aluminum nitride (AlN). The heat sink 8 is, for example, a heat dissipation component made of copper (Cu). As an example, the QCL 11 is die-bonded to the sub-mount bracket 16. The sub-mount bracket 16 is die-bonded to the heat sink 8. The heat sink 8 is secured to the support plate 61 with screws. On the heat sink 8, electrode pads (e.g., ceramic electrode pads) for supplying pulsed drive current to the QCL element 13 can be provided. These electrode pads are connected to the anode and cathode terminals of the QCL element 13.

[0047] Lenses 9A and 9B are, for example, aspherical lenses made of zinc selenide (ZnSe) or germanium (Ge), and are fixed to the heat sink 8 by ultraviolet-cured resin 17. Furthermore, in Figure 3 In the first case, lenses 9A and 9B are directly attached to the UV-curable resin 17, but the laser module 2 may also have lens holders to accommodate lenses 9A and 9B. In this case, each lens holder accommodating lenses 9A and 9B is fixed to the heat sink 8 via the UV-curable resin 17. Lens 9A is positioned relative to the QCL element 13 on the first end face 13a side to collimate the light emitted from the first end face 13a. Lens 9B is positioned relative to the QCL element 13 on the second end face 13b side to collimate the light emitted from the second end face 13b. After collimation by lens 9B, the light is output to the outside through the window 5a of the housing 5.

[0048] Light collimated by lens 9A is incident on the MEMS diffraction grating 12. The MEMS diffraction grating 12 diffracts and reflects the incident light, causing light of a specific wavelength in the incident light to return to the first end face 13a of the QCL element 13. That is, the MEMS diffraction grating 12 and the reflection reduction section 15 constitute a Littoral-type external resonator. As a result, the laser module 2 can amplify light of a specific wavelength and output it to the outside.

[0049] Furthermore, in the MEMS diffraction grating 12, as described later, the direction of the diffraction and reflection section 28, which causes the incident light to diffract and reflect, can be changed at high speed. As a result, the wavelength of the light returning from the MEMS diffraction grating 12 to the first end face 13a of the QCL element 13 is variable, and consequently, the wavelength of the output light L of the laser module 2 is variable.

[0050] The MEMS diffraction grating 12 includes a support portion 21, a pair of connecting portions 22, a movable portion 23, a coil 24, a pair of magnets 25, and a yoke 26. The MEMS diffraction grating 12 is configured as a MEMS device that allows the movable portion 23 to rock about an axis X. The MEMS diffraction grating 12 is fixed to the inclined surface 62a of the wall portion 62 of the support portion 6 via a mounting member 27. The mounting member 27 is a generally rectangular plate-shaped component when viewed from above (when viewed from a direction perpendicular to the plane on which at least the support portion 21 and the movable portion 23 are arranged).

[0051] The support portion 21 is a rectangular, flat frame when viewed from above. The support portion 21 supports the movable portion 23, etc., via a pair of connecting portions 22. Each connecting portion 22 is a rectangular, flat component that extends along the axis X when viewed from above. Each connecting portion 22 connects the movable portion 23 to the support portion 21 along the axis X in a manner that allows the movable portion 23 to rock freely about the axis X.

[0052] The movable part 23 is a flat, circular component when viewed from above, located inside the support part 21. As described above, the movable part 23 is freely connected to the support part 21. The support part 21, the connecting part 22, and the movable part 23 are integrally formed, for example, by being embedded into an SOI substrate.

[0053] A diffraction reflection section 28 is provided on the surface of the movable part 23 on the QCL 11 side. The diffraction reflection section 28 has a diffraction reflection surface that diffracts and reflects light emitted from the QCL 11. The diffraction reflection section 28 is provided, for example, all over the surface of the movable part 23, and is constructed by forming a resin layer with a diffraction grating pattern and a metal layer provided on the surface of the resin layer in a manner that extends along the diffraction grating pattern. Alternatively, the diffraction reflection section 28 may be provided on the movable part 23 and is constructed solely by forming a metal layer with a diffraction grating pattern. The diffraction grating pattern may be, for example, a blazed grating with a sawtooth cross section, a binary grating with a rectangular cross section, or a holographic grating with a sinusoidal cross section.

[0054] The coil 24 is made of a metal material such as copper and is embedded in a groove formed on the surface of the movable part 23. When viewed from above, the coil 24 is wound in a spiral shape multiple times. Wiring for external connection is electrically connected to the outer and inner ends of the coil 24. This wiring is provided, for example, throughout the support part 21, the connecting part 22, and the movable part 23, and is electrically connected to electrodes provided on the support part 21.

[0055] Magnets 25, 25 generate a magnetic field acting on coil 24. Magnets 25, 25 are formed in a cuboid shape and are arranged opposite a pair of sides of the support portion 21 that are parallel to the axis X. The magnetic poles of each magnet 25 are arranged, for example, in a Halbach arrangement. Alternatively, magnets 25, 25 can also be a pair of magnets arranged at predetermined intervals. A yoke 26 amplifies the magnetic force of magnets 25. The yoke 26, viewed from above, is rectangular and is arranged to surround the support portion 21 and magnets 25, 25.

[0056] In the MEMS diffraction grating 12, when current flows to the coil 24, the magnetic field generated by the magnets 25 produces a Lorentz force on the electrons flowing within the coil 24 in a predetermined direction. Thus, the coil 24 experiences a force in the predetermined direction. Therefore, by controlling the direction or magnitude of the current flowing to the coil 24, the movable part 23 (diffraction reflection part 28) can be made to rock around the axis X. Furthermore, by flowing a current to the coil 24 at a frequency corresponding to the resonant frequency of the movable part 23, the movable part 23 can be made to rock horizontally at a high speed at the resonant frequency. In this way, the coil 24 and the magnets 25 function as actuators to rock the movable part 23.

[0057] Four pillars B1 are erected on the first surface 61a of the support plate 61, extending along the thickness direction D. The material of the pillars B1 is, for example, a metal such as SUS. As an example, the four pillars B1 are arranged on the outer side of each corner of the region where the recess 61c is formed, when viewed from the thickness direction D. The upper end of each pillar B1, opposite to the end on the support plate 61 side, is connected to the first circuit board 31. For example, the upper end of each pillar B1 is fixed relative to the first circuit board 31 with screws.

[0058] The first circuit board 31 is a circuit board for controlling the operation of the QCL element 13. As an example, a pulse drive circuit for pulse-driven QCL element 13 is mounted on the first circuit board 31. The first circuit board 31 is electrically connected to the QCL element 13 via wiring (not shown). As an example, the first circuit board 31 is electrically connected to the QCL element 13 via wiring and electrode pads provided on the aforementioned heat sink 8. As an example, the first circuit board 31 is formed in a circular plate shape. The first circuit board 31 is positioned in the thickness direction D further away from the support plate 61 than the components (QCL element 13 and MEMS diffraction grating 12, etc.) disposed on the first surface 61a of the support plate 61 (i.e., above these components). The size of the first circuit board 31, viewed from the thickness direction D, is approximately the same as the size of the support plate 61. The first circuit board 31 overlaps with the support plate 61 when viewed from the thickness direction D.

[0059] Multiple (two) support pillars B2 are erected on the first surface 61a of the support plate 61, extending along the thickness direction D. The material of the support pillars B2 is, for example, the same metal material as the support pillars B1 (e.g., SUS). As an example, two support pillars B2 are arranged in the center of the housing 5, sandwiching components (QCL element 13 and MEMS diffraction grating 12, etc.) disposed on the first surface 61a of the support plate 61, and are positioned opposite each other in a direction perpendicular to the emission direction of the output light L and the thickness direction D. The upper end (opposite end) of each support pillar B2 on the support plate 61 side is connected to the second circuit board 32. For example, the upper end of each support pillar B2 is fixed relative to the second circuit board 32 with screws.

[0060] The second circuit board 32 is a circuit board on which a noise filter circuit is mounted. This noise filter circuit takes in a power signal from an external power source, removes noise contained in the power signal, and outputs a noise-removed power signal to the first circuit board 31. The noise filter circuit, for example, protects internal components such as the pulse drive circuit (first circuit board 31), the QCL element 13, and the MEMS diffraction grating 12 from the effects of electrostatic surges. The second circuit board 32 is smaller than the first circuit board 31 and is formed into a rectangular plate shape. The second circuit board 32 is positioned between the QCL element 13 and the first circuit board 31 in the thickness direction D. In this embodiment, the second circuit board 32 is positioned higher in the thickness direction D than the components (QCL element 13 and MEMS diffraction grating 12, etc.) disposed on the first surface 61a of the support plate 61, and is positioned lower in the thickness direction D than the first circuit board 31 (on the support plate 61 side).

[0061] When viewed from the thickness direction D, the second circuit board 32 overlaps with at least a portion of the QCL element 13 and at least a portion of the first circuit board 31. In this embodiment, when viewed from the thickness direction D, the entire second circuit board 32 overlaps with a portion of the first circuit board 31, and the entire QCL element 13 and MEMS diffraction grating 12 overlap with the second circuit board 32.

[0062] Here, compared to conventional semiconductor lasers, external resonant lasers utilizing gain media with quantum cascade structures (i.e., QCL element 13) require higher driving voltages and larger driving currents for pulse driving. Therefore, the first circuit board 31, on which the pulse driving circuit is mounted, exhibits higher heat generation. On the other hand, the noise filter circuit is non-heat-generating. That is, the first circuit board 31, on which the pulse driving circuit is mounted, has higher heat generation than the second circuit board 32, on which the noise filter circuit is mounted. Thus, by placing the second circuit board 32, which generates less heat than the first circuit board 31, between the first circuit board 31 and the components (QCL element 13 and MEMS diffraction grating 12, etc.) mounted on the support plate 61, heat transfer from the pulse driving circuit to the components (especially the QCL element 13) is suppressed.

[0063] [Control of the analysis device]

[0064] The analysis device 1 is controlled by the control device 4. For example... Figure 1 As shown, the control device 4 includes a diffraction grating control unit 41 for controlling the driving of the MEMS diffraction grating 12 and an arithmetic unit 42 for calculating the absorption spectrum based on the detection result of the photodetector 3. The control device 4 can be configured as, for example, a computer including an arithmetic circuit such as a CPU for performing arithmetic processing, a recording medium composed of memory such as RAM and ROM, and an input / output device. The control device 4 can also be configured as a computer including smart devices such as smartphones and tablet terminals. The control device 4 can operate by loading programs into the computer. Furthermore, the control device 4 can be configured to include a function generator for generating control pulses and a driver for controlling the cooling element 7. The function generator drives the QCL 11 and the MEMS diffraction grating 12 through the output of two channels linked by the program. Furthermore, the control device 4 can be configured to communicate with the first circuit board 31 and the second circuit board 32. For example, a timing signal that becomes the driving frequency is supplied from the function generator of the control device 4 to the first circuit board 31 (pulse driver circuit). The frequency of the pulse current can be varied, for example, in the range of 100kHz to 500kHz. Therefore, a pulse current with a pulse width of, for example, 100 ns is applied to the QCL element 13 from the first circuit board 31 (pulse drive circuit), causing laser oscillation with a light pulse width of 100 ns. Furthermore, the control device 4 can use the drive cycle of the MEMS diffraction grating 12 as a trigger to sample the output from the photodetector 3 via an oscilloscope or an AD converter. Moreover, the diffraction grating control unit 41 and the arithmetic unit 42 may not be composed of a single computer, but rather of different computers or electronic circuits. For example, the diffraction grating control unit 41 may also be composed of electronic circuitry included in the MEMS diffraction grating 12.

[0065] [Functions and Effects]

[0066] In the laser module 2 described above, a recess 61c is provided in the area overlapping with the QCL element 13 and the MEMS diffraction grating 12 on the second surface 61b of the support plate 61 (the surface opposite to the first surface 61a where the QCL element 13 and the MEMS diffraction grating 12 are arranged). The cooling element 7 is then inserted into this recess 61c. With this structure, the distance between the QCL element 13 and the cooling element 7 can be shortened compared to the case where the recess 61c is not provided on the support plate 61. This improves the cooling effect based on the cooling element 7. Furthermore, the portion of the support plate 61 without the recess 61c ensures sufficient thickness to maintain the strength of the support plate 61. This improves the physical stability of the support plate 61 compared to the case where the support plate 61 is uniformly thinned. Therefore, the deterioration of the optical characteristics of the laser module 2 (e.g., the emission characteristics of the laser) can be suppressed.

[0067] Furthermore, when viewed from the thickness direction D, at least a portion of the inner surface of the recess 61c of the support plate 61 can contact at least a portion of the outer edge of the cooling element 7. According to the above structure, since the cooling element 7 can be positioned via the recess 61c, product-to-product deviations can be prevented during the arrangement of the cooling element 7. Furthermore, in this embodiment, as an example, the size of the first substrate 71 of the cooling element 7 is the same as the size of the recess 61c. That is, the first substrate 71 is formed to a size that is perfectly accommodated within the recess 61c. In this case, the entire inner surface of the recess 61c can be in contact with the entire outer edge of the cooling element 7 (first substrate 71). That is, by embedding the cooling element 7 (first substrate 71) into the recess 61c, the stability of the cooling element 7 relative to the support plate 61 can be further improved.

[0068] Furthermore, by arranging the cooling element 7 in an overlapping manner with both the QCL element 13 and the MEMS diffraction grating 12, even if thermal deformation occurs in the cooling element 7, this thermal deformation is transmitted to both the cooling element 7 and the MEMS diffraction grating 12 in the same manner. More specifically, the effect of thermal deformation of the cooling element 7 is transmitted equally with respect to the heat sink 8 on which the QCL element 13 is mounted and the wall 62 on which the MEMS diffraction grating 12 is mounted. Thus, deviations in the relative positional relationship between the QCL element 13 and the MEMS diffraction grating 12 caused by thermal deformation of the cooling element 7 can be suppressed.

[0069] Furthermore, the MEMS diffraction grating 12 may have a diffraction-reflecting section 28 that diffracts and reflects a portion of the light emitted from the QCL element 13, and a portion of the light may be returned to the QCL element 13 by shaking the diffraction-reflecting section 28. That is, the MEMS diffraction grating 12 has a structure in which the diffraction grating (diffraction-reflecting section 28) and the movable mechanism (movable section 23) are integrally provided. Therefore, in the Littoral type laser module 2, the deterioration of optical properties can be suppressed and the cooling effect improved.

[0070] Furthermore, the circuit board for controlling the operation of the QCL element 13 (e.g., the circuit board corresponding to the first circuit board 31 described above) may not be disposed on the opposite side of the support plate 61 in the cooling element 7 (i.e., the side opposite to the bottom wall 51 of the cooling element 7). In this case, by not providing a circuit board as a heat source on the opposite side of the support plate 61 in the cooling element 7, the heat dissipation of the cooling element 7 can be prevented from being obstructed. As a result, the cooling effect based on the cooling element 7 can be further improved. More specifically, as described above, the first circuit board 31 on which the pulse drive circuit is mounted generates a large amount of heat. By configuring the first circuit board 31 and the support plate 61 in such a thermally separated manner, the thermal influence on the light emission characteristics of the laser can be suppressed.

[0071] Furthermore, on the opposite side of the support plate 61 in the cooling element 7 (i.e., the side opposite to the bottom wall 51 of the cooling element 7), an auxiliary cooling element 33 can be disposed to further cool the cooling element 7. In this case, the cooling effect can be further improved by the auxiliary cooling element 33. In addition, such a structure can be achieved by disposing of a conventional circuit board (e.g., the circuit board corresponding to the first circuit board 31 described above) that is generally disposed below the cooling element 7 within the housing 5.

[0072] Furthermore, the laser module 2 may also include: multiple pillars (in this embodiment, pillars B1 and B2) erected on the first surface 61a of the support plate 61 and extending along the thickness direction D; and pillar connecting members (in this embodiment, each of the first circuit board 31 and the second circuit board 32) disposed in the thickness direction D at a position further away from the support plate 61 than the QCL element 13, and connected to the ends of each of the multiple pillars B1 and B2. According to the above structure, since the support plate 61 is properly supported by the multiple pillars and pillar connecting members, the physical stability of the support plate 61 can be further improved. Therefore, the deterioration of the optical characteristics of the laser module 2 can be more effectively suppressed.

[0073] Furthermore, the laser module 2 may also include multiple (four in this embodiment) pillars B1 and a first circuit board 31 connected to the ends of each of the multiple pillars B1. The first circuit board 31 may also be a circuit board for controlling the operation of the QCL element 13. In this embodiment, as an example, the first circuit board 31 is a circuit board on which the pulse drive circuit is mounted. Assuming the first circuit board 31 is in contact with the cooling element 7, heat generated from the first circuit board 31 may be transferred to the QCL element 13 via the cooling element 7 and the support plate 61. Alternatively, the heat generated from the first circuit board 31 may hinder the heat dissipation of the cooling element 7. On the other hand, according to the structure described above that supports the first circuit board 31 via multiple pillars B1, by placing the first circuit board 31, which is a heat source, away from the cooling element 7, the above-mentioned problems can be avoided. Furthermore, as described above, the physical stability of the support plate 61 can be improved. That is, the first circuit board 31 can function as the pillar connecting member described above. Furthermore, by assembling the pulse drive circuit into the housing 5, the overall miniaturization of the laser source (laser module 2) can be achieved.

[0074] Furthermore, the laser module 2 may also include a noise filter circuit. The noise filter circuit receives a power signal from an external power source, removes noise contained in the power signal, and outputs a noise-removed power signal to the first circuit board 31. In this embodiment, the noise filter circuit is mounted on the second circuit board 32. According to the above structure, since noise superimposed on the power signal is removed by the noise filter circuit, damage to the first circuit board 31 caused by electrostatic surges or the like can be prevented. Furthermore, when power signals are supplied to the QCL element 13 and the MEMS diffraction grating 12 via the first circuit board 31, damage to the QCL element 13 and the MEMS diffraction grating 12 can also be prevented.

[0075] Furthermore, the laser module 2 may also include multiple (two in this embodiment) pillars B2 and a second circuit board 32 disposed in the thickness direction D between the QCL element 13 and the first circuit board 31 and connected to the ends of each of the multiple pillars B2. Here, the first circuit board 31 has a higher heat generation capacity than the second circuit board 32. According to the above structure, since the heat generated from the first circuit board 31 is shielded by the second circuit board 32, heat transfer from the first circuit board 31 to the QCL element 13 can be suppressed.

[0076] Furthermore, when viewed from the thickness direction D, the second circuit board 32 may overlap with at least a portion of the QCL element 13 (in this embodiment, as an example, the entire QCL element 13) and at least a portion of the first circuit board 31. According to the above structure, heat transfer from the first circuit board 31 to the QCL element 13 can be more effectively suppressed.

[0077] Furthermore, the second circuit board 32 can also be a circuit board on which the aforementioned noise filter circuit is mounted. According to the above structure, the board on which the noise filter circuit is mounted can function as a second circuit board 32 to shield the heat generated from the first circuit board 31. Therefore, compared to a structure that separately provides a component for shielding heat from the first circuit board 31 and a board on which the noise filter circuit is mounted, miniaturization of the module (housing 5) can be achieved. Furthermore, in this embodiment, the size of the module depends on the size of the first circuit board 31 (the diameter of the board on the circular plate). As in the above embodiment, by separating the pulse drive circuit (first circuit board 31) and the noise filter circuit (second circuit board 32), miniaturization of the first circuit board 31 can be achieved, thereby miniaturization of the module. More specifically, if the size of the first circuit board 31 can be reduced, the size of the support plate 61 supporting the first circuit board 31 can also be reduced accordingly. As a result, the width and depth of the housing 5 can be reduced (i.e., as shown in the previous embodiment). Figure 2 The longitudinal and transverse dimensions of the frame 5 are shown when viewed from the thickness direction D.

[0078] Furthermore, the laser module 2 may also include a heat-conducting sheet 34 disposed within the recess 61c of the support plate 61 between the support plate 61 and the cooling element 7. According to the above structure, the heat transfer between the support plate 61 and the cooling element 7 can be improved, thus further enhancing the cooling effect.

[0079] Furthermore, a recess 51b may be provided on the side of the bottom wall 51 on the side of the cooling element 7, for inserting at least a portion of the bottom wall 51 side of the cooling element 7 (i.e., at least a portion of the bottom wall 51 side of the second substrate 72). According to the above structure, the cooling element 7 can be easily positioned relative to the bottom wall 51 via the recess 51b. Furthermore, in this embodiment, as an example, the size of the second substrate 72 of the cooling element 7 is the same as the size of the recess 51b. That is, the second substrate 72 is formed to a size that is perfectly accommodated within the recess 51b. In this case, the entire inner surface of the recess 51b can be in contact with the entire outer edge of the cooling element 7 (the second substrate 72). That is, by embedding the cooling element 7 (the second substrate 72) into the recess 51b, the stability of the cooling element 7 relative to the bottom wall 51 can be further improved.

[0080] [Variation Example]

[0081] The present invention has been described above as one embodiment, but the present invention is not limited to the above embodiment. The materials and shapes of the various structures are not limited to those described above, and various materials and shapes can be used. For example, in the above embodiment, the external resonator can also be configured as a Littmann type. In this case, the laser module 2 can, for example, replace the MEMS diffraction grating 12 integrally formed with the movable mechanism (movable part 23) and have a fixed (non-movable) diffraction grating and a movable mirror for reflecting the primary diffracted light of the diffraction grating.

[0082] Furthermore, the first circuit board 31 need not be disposed within the frame 5. The same applies to the second circuit board 32. In addition, in order to improve the physical stability of the support plate 61, the laser module 2 may also include: a support connecting member (e.g., a plate-shaped member extending parallel to the support plate 61) other than the first circuit board 31 and the second circuit board 32, and a support connecting the support connecting member and the support plate 61.

[0083] Furthermore, in the above embodiment, the bottom wall 51 of the housing 5 functions as a base plate for mounting the support plate 61, but the support plate 61 may also be mounted on a different base plate than the bottom wall 51 (for example, a substrate disposed on the bottom wall 51 within the housing 5). In this case, the auxiliary cooling element 33 may also be disposed between the base plate and the bottom wall 51.

[0084] Furthermore, if the cooling element 7 alone provides sufficient cooling, the auxiliary cooling element 33 can be omitted. Similarly, the heat transfer plate 34 can also be omitted.

[0085] Furthermore, in the above embodiment, when viewed from the thickness direction D, the recess 61c of the support plate 61 is formed to overlap entirely with the sub-mount bracket 16 on which the QCL element 13 is mounted and the wall portion 62 on which the MEMS diffraction grating 12 is mounted. However, the range and size of the area where the recess 61c is formed are not limited to the above embodiment. The recess 61c may overlap at least a portion of the QCL element 13. Preferably, the recess 61c is formed to overlap entirely with the QCL element 13. For example, the recess 61c may also be formed to overlap entirely with the QCL element 13 and a portion of the sub-mount bracket 16. More preferably, the recess 61c is formed to overlap entirely with the sub-mount bracket 16. Furthermore, when viewed from the thickness direction D, if the lens 9B is exposed from the sub-mount bracket 16, it is preferable that the recess 61c is formed to overlap entirely with the sub-mount bracket 16 and the lens 9B. Furthermore, the recess 61c may overlap at least with the diffraction reflection portion 28 on which the diffraction grating is formed in the MEMS diffraction grating 12. Preferably, the recess 61c is formed in a manner that overlaps entirely with the wall portion 62, as in this embodiment.

[0086] Regarding the extent and size of the cooling element 7, it can be said to be the same as the extent and size of the recess 61c described above. That is, the cooling element 7 can overlap at least a portion of the QCL element 13. Preferably, the cooling element 7 is formed to completely overlap with the QCL element 13. For example, the cooling element 7 can also be formed to completely overlap with the QCL element 13 and a portion of the sub-mount bracket 16. More preferably, the cooling element 7 is formed to completely overlap with the sub-mount bracket 16. Furthermore, when viewed from the thickness direction D, if the lens 9B is exposed from the sub-mount bracket 16, it is preferable that the cooling element 7 is formed to completely overlap with the sub-mount bracket 16 and the lens 9B. In addition, the cooling element 7 can overlap at least with the diffraction reflection portion 28 in which the diffraction grating is formed in the MEMS diffraction grating 12. Preferably, the cooling element 7 is formed to completely overlap with the wall portion 62 as in this embodiment.

[0087] Furthermore, in the above embodiment, the area of ​​the portion of the support plate 61 where the recess 61c is not formed (the wall thickness portion other than the recess 61c as viewed from the thickness direction D) is larger than the area of ​​the recess 61c (i.e., the thin-walled portion). This appropriately ensures the physical stability of the support plate 61. However, the area of ​​the wall thickness portion (the portion other than the recess 61c) may also be smaller than the area of ​​the thin-walled portion (the recess 61c).

[0088] Explanation of symbols

[0089] 1…Analytical device, 2…External resonant laser module, 3…Photodetector, 7…Cooling element, 11…Quantum cascade laser, 12…MEMS diffraction grating, 13…Quantum cascade laser element, 28…Diffraction reflection section, 31…First circuit board (support connecting component), 32…Second circuit board (support connecting component), 33…Auxiliary cooling element, 34…Heat conduction sheet, 51…Bottom wall (base plate), 51b…Recess, 61…Support plate, 61a…First surface, 61b…Second surface, 61c…Recess, B1, B2…Supports, D…Thickness direction.

Claims

1. An external resonant laser module, characterized in that: have: Quantum cascade laser components; A diffraction grating that causes a portion of the light emitted from the quantum cascade laser element to be diffracted and reflected back to the quantum cascade laser element; A support plate having a first surface on which the quantum cascade laser element and the diffraction grating are disposed, and a second surface opposite to the first surface; and A cooling element is configured on the second surface side of the support plate, overlapping the quantum cascade laser element and the diffraction grating when viewed from the thickness direction of the support plate. The cooling element includes a first substrate disposed on the support plate side, a second substrate disposed on the opposite side of the first substrate on the support plate side, and a heat-moving portion disposed between the first substrate and the second substrate. In the second surface of the support plate, in the region that overlaps at least with the quantum cascade laser element and the diffraction grating when viewed from the thickness direction of the support plate, a recess is provided in the direction from the second surface toward the first surface. At least a portion of the support plate side of the first substrate is inserted into the recess.

2. The external resonant laser module according to claim 1, characterized in that: When viewed from the thickness direction of the support plate, at least a portion of the inner surface of the recess is in contact with at least a portion of the outer edge of the first substrate.

3. The external resonant laser module according to claim 1, characterized in that: The diffraction grating has a diffraction and reflection section that diffracts and reflects a portion of the light emitted from the quantum cascade laser element, and by shaking the diffraction and reflection section, a portion of the light is returned to the quantum cascade laser element.

4. The external resonant laser module according to claim 2, characterized in that: The diffraction grating has a diffraction and reflection section that diffracts and reflects a portion of the light emitted from the quantum cascade laser element, and by shaking the diffraction and reflection section, a portion of the light is returned to the quantum cascade laser element.

5. The external resonant laser module according to claim 1, characterized in that: On the opposite side of the support plate in the cooling element, no circuit board for controlling the operation of the quantum cascade laser element is disposed.

6. The external resonant laser module according to claim 2, characterized in that: On the opposite side of the support plate in the cooling element, no circuit board for controlling the operation of the quantum cascade laser element is disposed.

7. The external resonant laser module according to claim 3, characterized in that: On the opposite side of the support plate in the cooling element, no circuit board for controlling the operation of the quantum cascade laser element is disposed.

8. The external resonant laser module according to claim 4, characterized in that: On the opposite side of the support plate in the cooling element, no circuit board for controlling the operation of the quantum cascade laser element is disposed.

9. The external resonant laser module according to claim 5, characterized in that: An auxiliary cooling element is disposed on the opposite side of the support plate side of the cooling element to further cool the cooling element.

10. The external resonant laser module according to claim 6, characterized in that: An auxiliary cooling element is disposed on the opposite side of the support plate side of the cooling element to further cool the cooling element.

11. The external resonant laser module according to claim 7, characterized in that: An auxiliary cooling element is disposed on the opposite side of the support plate side of the cooling element to further cool the cooling element.

12. The external resonant laser module according to claim 8, characterized in that: An auxiliary cooling element is disposed on the opposite side of the support plate side of the cooling element to further cool the cooling element.

13. The external resonant laser module according to any one of claims 1 to 12, characterized in that: Further features include: Multiple support pillars, erected on the first surface of the support plate and extending along the thickness direction of the support plate; and A strut connecting component is disposed in the thickness direction of the support plate at a position further away from the support plate than the quantum cascade laser element, and is connected to the respective ends of the plurality of struts.

14. The external resonant laser module according to any one of claims 1 to 12, characterized in that: Further features include: A plurality of first support columns, which are erected on the first surface of the support plate and extend along the thickness direction of the support plate; and A first circuit board is disposed in the thickness direction of the support plate at a position farther away from the support plate than the quantum cascade laser element, and is connected to the ends of each of the plurality of first pillars. The first circuit board is a circuit board used to control the operation of the quantum cascade laser element.

15. The external resonant laser module according to claim 14, characterized in that: It further includes: a noise filter circuit that takes in a power signal from an external power source, removes noise contained in the power signal, and outputs the noise-removed power signal to the first circuit board.

16. The external resonant laser module according to claim 14, characterized in that: Further features include: A plurality of second support pillars, which are erected on the first surface of the support plate and extend along the thickness direction of the support plate; and A second circuit board is disposed in the thickness direction of the support plate between the quantum cascade laser element and the first circuit board, and is connected to the ends of each of the plurality of second pillars. The first circuit board has higher heat generation than the second circuit board.

17. The external resonant laser module according to claim 16, characterized in that: When viewed from the thickness direction of the support plate, the second circuit board overlaps with at least a portion of the quantum cascade laser element and at least a portion of the first circuit board.

18. The external resonant laser module according to claim 16, characterized in that: The second circuit board is a circuit board on which a noise filter circuit is mounted. The noise filter circuit takes in a power signal from an external power source, removes the noise contained in the power signal, and outputs the noise-removed power signal to the first circuit board.

19. The external resonant laser module according to claim 17, characterized in that: The second circuit board is a circuit board on which a noise filter circuit is mounted. The noise filter circuit takes in a power signal from an external power source, removes the noise contained in the power signal, and outputs the noise-removed power signal to the first circuit board.

20. The external resonant laser module according to any one of claims 1 to 12, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

21. The external resonant laser module according to claim 13, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

22. The external resonant laser module according to claim 14, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

23. The external resonant laser module according to claim 15, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

24. The external resonant laser module according to claim 16, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

25. The external resonant laser module according to claim 17, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

26. The external resonant laser module according to claim 18, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

27. The external resonant laser module according to claim 19, characterized in that: It further comprises: a heat-conducting sheet disposed within the recess of the support plate, between the support plate and the cooling element.

28. The external resonant laser module according to any one of claims 1 to 12, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

29. The external resonant laser module according to claim 13, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

30. The external resonant laser module according to claim 14, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

31. The external resonant laser module according to claim 15, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

32. The external resonant laser module according to claim 16, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

33. The external resonant laser module according to claim 17, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

34. The external resonant laser module according to claim 18, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

35. The external resonant laser module according to claim 19, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

36. The external resonant laser module according to claim 20, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

37. The external resonant laser module according to claim 21, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

38. The external resonant laser module according to claim 22, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

39. The external resonant laser module according to claim 23, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

40. The external resonant laser module according to claim 24, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

41. The external resonant laser module according to claim 25, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

42. The external resonant laser module according to claim 26, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

43. The external resonant laser module according to claim 27, characterized in that: It further includes: a base plate disposed on the opposite side of the support plate side of the cooling element. On the cooling element side of the base plate, a recess is provided that inserts into at least a portion of the base plate side of the second substrate.

Images