CN-116113791-B - Quantum cascade laser module

CN116113791BCN 116113791 BCN116113791 BCN 116113791BCN-116113791-B

Abstract

The QCL module of one embodiment of the present invention includes a package accommodating a QCL element and provided with a window member taking out laser light emitted from the QCL element to the outside, a lens holding member holding a lens on which the laser light emitted from the window member is incident, a cooling fan cooling the package, and a base holding the package, the lens holding member, and the cooling fan. The package and the lens holding member are fastened together with respect to the base by a common screw member.

Inventors

Qiu Caozhida
DOUGAKIUCHI TATSUO

Assignees

浜松光子学株式会社

Dates

Publication Date: 20260512
Application Date: 20210819
Priority Date: 20200915

Claims (7)

1. A quantum cascade laser module, wherein, Comprising the following steps: A package that accommodates a quantum cascade laser element and is provided with a window member that takes out laser light emitted from the quantum cascade laser element to the outside; a lens holding member that holds a lens on which the laser light emitted from the window member is incident; A cooling fan for cooling the package, and A base that holds the package, the lens holding member, and the cooling fan, The base has a1 st and a 2 nd face on opposite sides from each other, The package and the lens holding member are fastened to the chassis by a common shaft member in a state of being disposed on the 1 st surface side of the chassis, The cooling fan is fixed to the base in a state of being disposed on the 2 nd surface side of the base.
2. The quantum cascade laser module of claim 1, wherein, The package is disposed between the base and the lens holding member so that the window member faces the lens, The package and the lens holding member are fastened together with respect to the base by the lens holding member.
3. The quantum cascade laser module of claim 2, wherein, Further comprising a spacer arranged between the lens holding member and the base, The package has a flange abutting the base and extending along the base, The spacer is disposed between the base-side surface of the lens holding member and the lens holding member-side surface of the flange, and a gap is formed between the lens holding member and the window member.
4. The quantum cascade laser module of claim 3, wherein, The flange has a1 st flange and a 2 nd flange formed on both sides sandwiching the window member, The spacer has a1 st spacer arranged between the base-side surface of the lens holding member and the lens holding member-side surface of the 1 st flange, and a2 nd spacer arranged between the base-side surface of the lens holding member and the lens holding member-side surface of the 2 nd flange.
5. The quantum cascade laser module of claim 3 or 4, wherein, Insertion holes through which the shaft member is inserted are formed in the lens holding member, the spacer, the flange, and the base, respectively, The lens holding member, the spacer, and the flange are fastened together with respect to the base by fastening the lens holding member with respect to the base by the shaft member inserted through the insertion holes of the lens holding member, the spacer, the flange, and the base, respectively.
6. The quantum cascade laser module of claim 3 or 4, wherein, Insertion holes through which the shaft member is inserted are formed in the lens holding member and the base, respectively, The lens holding member, the spacer, and the flange are fastened together with respect to the base by fastening the lens holding member with respect to the base by the shaft member inserted through the insertion holes of the lens holding member and the base, respectively, in a state where the spacer and the flange are arranged between the lens holding member and the base.
7. The quantum cascade laser module of any of claims 3-6, wherein, The spacer is formed of a material having a lower thermal conductivity than the base.

Description

Quantum cascade laser module Technical Field The invention relates to a quantum cascade laser module. Background Conventionally, there are known modules in which a light source element, a lens holder (laser holder), and a cooling fan for cooling the light source element are integrated (for example, refer to patent documents 1 and 2). Patent document 1 discloses a structure including an LED unit (LED substrate and LED package), an illumination section (lens group), and a cooling fan. In the structure described in patent document 1, a mounting member to which an illumination unit is mounted and an LED board are fixed to a base, respectively. Patent document 2 discloses a structure in which a light source module, a lens holder, and a cooling fan are fixed to the light source holder. In the structure described in patent document 2, the light source module and the lens holder are fixed to the light source holder, respectively. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2017-188256 Patent document 2 Japanese patent application laid-open No. 2019-096637 Disclosure of Invention Problems to be solved by the invention As the light source of the above-described module, a quantum cascade laser (hereinafter, referred to as "QCL") may be used. Modules comprising QCL are used for example for concentration measurement of gases and the like. For example, a gas cell in which a gas to be measured is sealed is arranged between the module and the photodetector, and laser light emitted from the module is allowed to pass through the gas cell, and the laser light passing through the gas cell is detected by the photodetector, so that the concentration of the gas in the gas cell (the absorbance of the laser light) can be measured. QCL has excellent monochromaticity (i.e., excellent wavelength resolution), and thus can be suitably used for concentration measurement of the gas as described above. On the other hand, optical noise is generated in principle due to the excellent monochromaticity as described above. More specifically, streak noise (interference noise) is generated due to interference components between the radiation end face of the QCL and the interface of the lens included in the module. If the optical condition (e.g., fabry-perot resonator length) between the QCL and the lens does not change over time, the optical noise can be handled as an invariant, and therefore can be removed by a background (background) operation. However, in the case where the module includes the cooling fan as described above, there is a possibility that a deviation may occur between the vibration of the QCL and the vibration of the lens due to the vibration of the cooling fan. In particular, in the case where the light source and the lens are fixed to base members (i.e., the base in patent document 1 and the light source holder in patent document 2) as in the structures described in patent documents 1 and 2, the vibration of the QCL and the vibration of the lens are different in phase, and the positional relationship (i.e., the optical path length) between the QCL and the lens is liable to vary with time. In this case, since the optical condition varies with time, the optical noise cannot be handled as an invariant. That is, the optical noise cannot be removed by the background operation. Therefore, the sensitivity (detection limit) in the measurement as described above is limited. Therefore, in order to suppress the occurrence of vibration which is a factor of temporal fluctuation of the optical condition, it is also considered to use a water jacket or the like which does not generate vibration instead of the cooling fan. However, in this case, a device for circulating the cooling water is required, and therefore, the entire module is enlarged and complicated, and the maintenance and repair costs are also increased. Accordingly, an object of an aspect of the present invention is to provide a quantum cascade laser module capable of reducing optical noise caused by temporal variation of optical conditions in a structure including a cooling fan. Means for solving the problems The quantum cascade laser module of one aspect of the present invention includes a package that accommodates a quantum cascade laser element and is provided with a window member that takes out laser light emitted from the quantum cascade laser element to the outside, a lens holding member that holds a lens on which the laser light emitted from the window member is incident, a cooling fan that cools the package, and a base that holds the package, the lens holding member, and the cooling fan, the package and the lens holding member being fastened together with respect to the base by a common shaft member. The quantum cascade laser module described above includes a cooling fan for cooling the package. According to such a configuration, compared with the case where a cooling mechanism of another type (for example, a water coo