Grating spectrometer

Abstract

The invention discloses a grating spectrometer. The grating spectrometer comprises a shell, an imaging structure, a dispersion grating and a temperature control structure. An accommodating cavity is formed in the shell, and an imaging structure is arranged on one side of the shell; the dispersion grating is arranged in the accommodating cavity, and light emitted by the imaging structure faces the dispersion grating; the temperature control structure comprises a heating piece and a refrigeration assembly, the heating piece is arranged on the side, away from the imaging structure, of the dispersion grating in an attached mode, the refrigeration assembly is installed on the shell, and the refrigeration end of the refrigeration assembly extends into the containing cavity. According to the structure, different spectral resolution requirements can be met without replacing the dispersion grating, and installation and adjustment errors and influences on the system sensitivity and the signal-to-noise ratio are avoided. The method has very positive significance in application in the fields of low-temperature spectral imaging and the like, is simpler to operate and higher in sensitivity, and has wider application fields.

Description

Technical Field

[0001] The invention relates to the technical field of spectrometers, and in particular to a grating spectrometer. Background Art

[0002] Grating spectrometer is a scientific instrument that decomposes complex light into spectral lines. Grating is the most important component of the spectrometer. The number of grating lines will directly affect the spectrum splitting effect and spectral resolution. Grating is composed of substrate material, periodic stripes, etching or deposition layer. Diffraction grating made of ordinary glass is prone to thermal expansion and contraction in high or low temperature environment. This causes the size of the grating to change, that is, the grating lines become denser or sparser. Since the spectral resolution is proportional to the number of grating lines, it will cause the spectral resolution to change.

[0003] In some application scenarios, it is necessary to replace gratings with different lines on the same spectrometer to meet imaging requirements of different resolutions. Each replacement and adjustment will have a certain installation error, which will affect the resolution and wavelength accuracy of the instrument. In addition, gratings of different materials and manufacturing processes may introduce different degrees of optical loss or scattering. Replacing the grating may change the sensitivity and signal-to-noise ratio of the instrument. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that each replacement and adjustment will have a certain installation error, thereby affecting the resolution and wavelength accuracy of the instrument.

[0005] To this end, the present invention provides a grating spectrometer, comprising:

[0006] A housing, wherein a receiving cavity is provided in the housing, and an imaging structure is provided on one side of the housing;

[0007] A dispersion grating, wherein the dispersion grating is arranged in the accommodating cavity, and the light emitted by the imaging structure is directed toward the dispersion grating;

[0008] The temperature control structure comprises a heating element and a cooling assembly, wherein the heating element is arranged on a side of the dispersion grating away from the imaging structure, the cooling assembly is installed on the shell, and the cooling end of the cooling assembly extends into the accommodating cavity.

[0009] Optionally, the above-mentioned refrigeration component includes:

[0010] A refrigeration system, wherein the refrigeration system is installed on a side of the housing away from the imaging structure, and a refrigeration end of the refrigeration system extends into the accommodating cavity;

[0011] A cold chain, one end of which is connected to the refrigeration end of the refrigeration system, and the other end of which extends into the accommodating cavity.

[0012] Optionally, the above-mentioned refrigeration component includes:

[0013] A refrigeration system, wherein the refrigeration system is installed on a side of the housing away from the imaging structure, and a refrigeration end of the refrigeration system extends into the accommodating cavity;

[0014] A cold chain, one end of which is connected to the refrigeration end of the refrigeration system, and the other end of which extends into the accommodating cavity.

[0015] Optionally, one end of the cold chain away from the refrigeration system is attached to the dispersion grating.

[0016] Optionally, the temperature control structure further comprises a temperature measuring component, a temperature measuring end of the temperature measuring component is closely attached to a side surface of the dispersion grating, and the temperature measuring component is used to detect the temperature of the dispersion grating.

[0017] Optionally, the grating spectrometer further comprises a control module, and the control module is installed outside the housing;

[0018] The control module is also connected to the temperature measuring component to receive the temperature parameter measured by the temperature measuring component and control the heating component and the cooling component to adjust the temperature of the dispersion grating.

[0019] Optionally, the edge of the above-mentioned dispersion grating is in contact with the inner edge of the accommodating cavity.

[0020] Optionally, the substrate of the dispersion grating is made of a substrate with a thermal expansion coefficient of 0.5×10 -6 ~1×10 -6 / k material;

[0021] The periodic fringes of the dispersion grating adopt a thermal expansion coefficient of 2.0×10 -6 ~2.5×10 -6 / k material.

[0022] Optionally, the above imaging structure includes:

[0023] An optical window, wherein the optical window is provided at an end of the housing away from the temperature control structure;

[0024] An imaging system is installed between the optical window and the dispersion grating. After the light source passes through the optical window and irradiates the imaging system, it directly irradiates the dispersion grating.

[0025] Optionally, the above-mentioned shell is a vacuum dewar.

[0026] The technical solution provided by the present invention has the following advantages:

[0027] 1. A grating spectrometer provided by the present invention comprises a housing, an imaging structure, a dispersion grating and a temperature control structure. A housing cavity is provided in the housing, and an imaging structure is provided on one side of the housing; the dispersion grating is provided in the housing cavity, and the light emitted by the imaging structure is directed toward the dispersion grating; the temperature control structure comprises a heating element and a cooling component, the heating element is provided on a side of the dispersion grating away from the imaging structure, the cooling component is installed on the housing, and the cooling end of the cooling component extends into the housing cavity.

[0028] When the grating spectrometer is working, all objects above K will emit infrared rays, so the infrared imaging system is easily affected by the ambient temperature. If the optical system itself works at room temperature, it will bring a lot of stray radiation. The refrigeration system works throughout the process to cool the dispersion grating and other components, and the cold chain provides a low temperature environment for the entire spectral imaging system. When the entire optical system is cooled by the cold chain, the system stray light will be greatly reduced, the stray light will be effectively suppressed, the effective signal received by the detection will be increased, and the resolution of the spectrometer will be greatly improved. In a low temperature environment, the spectrometer's resolution precision control capability is even better. This structure realizes that different spectral resolution requirements can be met without replacing the dispersion grating, avoiding installation errors and the impact on system sensitivity and signal-to-noise ratio, and can achieve spectral splitting of an ultra-wide band of 6μm-40μm. It has a very positive significance for applications in fields such as low-temperature spectral imaging, with simpler operation, higher sensitivity, and a wider range of applications.

[0029] 2. The heating element and the cold chain are both close to the astigmatism grating. The heating element is close to the grating, so that the optical system's lenses and detectors will be affected as little as possible by the heating element, avoiding the infrared system imaging being affected by the high temperature environment. If the heating element is not close to the grating, it may affect the ambient temperature of the optical lenses and detectors, increase stray radiation, and bring background noise.

[0030] By placing the heating element and the cold chain in close contact with the dispersion grating, the heating efficiency can be increased and the adjustment speed can be improved. After the heating element is heated and the heating is removed, compared with a grating spectrometer without a refrigeration structure, the cold chain is more effective in cooling the dispersion grating, and the temperature of the dispersion grating returns to its original state very quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of the structure of the grating spectrometer provided by the present invention;

[0033] Figure 2 A light path diagram of an imaging system in a grating spectrometer of the present invention;

[0034] Figure 3 It is a connection diagram of the dispersion grating, the heating element, the cooling assembly, the temperature measuring element and the control module of the grating spectrometer of the present invention;

[0035] Description of reference numerals:

[0036] 1-housing; 2-optical window;

[0037] 3- Imaging system;

[0038] 4 – dispersion grating;

[0039] 5-Heating element;

[0040] 6-refrigeration components; 61-refrigeration system; 62-cold chain;

[0041] 7-Temperature measuring device;

[0042] 8 – Control module. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] Example

[0048] This embodiment provides a grating spectrometer, such as Figures 1 to 3 As shown, it includes a housing 1, an imaging structure, a dispersion grating 4 and a temperature control structure.

[0049] The shell 1 is a vacuum dewar, and the shell 1 is a hollow structure with a containing cavity arranged therein. Figure 1 As shown, the housing 1 is provided with an imaging structure, a dispersion grating 4 and a temperature control structure in sequence.

[0050] like Figure 1 As shown, the imaging structure includes an optical window 2 and an imaging system 3. The optical window 2 is opened on the left side of the housing 1 away from the temperature control structure. The imaging system 3 is installed on the right side of the optical window 2. The imaging system 3 is located in the accommodating cavity. The optical material on the optical window 2 can be replaced. The imaging system 3 adopts an off-axis reflective spectral imaging system 3. The specific design of the optical path is as follows Figure 2 After the light source passes through the optical window 2 and irradiates the imaging system 3 , it directly irradiates the dispersion grating 4 .

[0051] like Figure 1 As shown, the dispersion grating 4 is located in the accommodating cavity, the edge of the dispersion grating 4 is in contact with the inner edge of the accommodating cavity, the dispersion grating 4 is located on the right side of the imaging system 3, that is, the imaging system 3 is located between the optical window 2 and the dispersion grating 4, and the substrate of the dispersion grating 4 is made of a substrate with a thermal expansion coefficient of 0.5×10 -6 ~1×10 -6 / k materials, such as fused quartz, Invar alloy, etc., with good stability; the periodic stripes of the dispersion grating 4 are made of a material with a thermal expansion coefficient of 2.0×10 -6 ~2.5×10 -6 / k materials, such as yellow aluminum alloy, copper, magnesium alloy, etc.

[0052] like Figure 1As shown, the temperature control structure includes a heating element 5 and a refrigeration assembly 6. The heating element 5 can be a heating device such as a heating wire, which is not specifically limited, and can achieve a device base shell with a heating effect. The heating element 5 is fitted on the side of the dispersion grating 4 away from the imaging structure. The refrigeration assembly 6 includes a refrigeration system 61 and a cold chain 62. The refrigeration system 61 is installed on the side of the shell 1 away from the imaging structure. The refrigeration end on the left side of the refrigeration system 61 passes through the right arm of the shell 1 and extends into the accommodating cavity; the cold chain 62 is located in the accommodating cavity, one end is connected to the refrigeration end of the refrigeration system 61, and the other end is fitted with the dispersion grating 4. Specifically, there are many cold chains 62, one part of which is connected to the optical lens, one part is connected to the dispersion grating 4, one part is connected to the detector, and one part is connected to the cold screen. During the operation, the refrigeration system 61 is turned on all the time. Only the dispersion grating 4 is connected to both the cold chain 62 and the heater 5. The heater 5 is adjusted according to demand to achieve the purpose of controlling the temperature of the dispersion grating 4. Therefore, in the entire system, only the grating temperature will be changed by the change of the heater 5, avoiding the situation where the temperature of the dispersion grating 4 does not match the temperature of other components.

[0053] like Figure 1 As shown, the temperature control structure also includes a temperature measuring element 7, and the temperature measuring end of the temperature measuring element 7 is closely attached to the side of the dispersion grating 4. The grating spectrometer also includes a control module 8, which is installed outside the housing 1; the control module 8 is also connected to the temperature measuring element 7 to receive the temperature parameter measured by the temperature measuring element 7 and control the heating element 5 and the cooling assembly 6 to adjust the temperature of the dispersion grating 4.

[0054] When the grating spectrometer is working, all objects above 0K will emit infrared rays, so the infrared imaging system 3 is easily affected by the ambient temperature. If the optical system itself works at room temperature, it will bring a lot of stray radiation. The refrigeration system 61 works throughout the process to cool the dispersion grating 4 and other components, and the cold chain 62 provides a low temperature environment for the entire spectral imaging system 3. When the entire optical system is cooled by the cold chain 62, the system stray light will be greatly reduced, effectively suppressing the stray light, and the effective signal received by the detection will be increased, greatly improving the resolution of the spectrometer. In a low temperature environment, the spectrometer's ability to accurately control the resolution is even better.

[0055] like Figure 3 As shown, when the dispersion grating 4 needs to be adjusted, the temperature data of the dispersion grating 4 is measured in real time by the temperature measuring element 7 and transmitted to the control module 8. The control module 8 drives the heating element 5 or the refrigeration system 61 to change the grating temperature by receiving the temperature data of the temperature measuring element 7. The temperature change will cause the expansion or contraction of the dispersion grating 4 material, so that the number of grating lines will change, thereby adjusting the spectral resolution, thereby adjusting the resolution of the grating spectrometer. By setting the temperature measuring element 7 and the control module 8, the dispersion grating 4 can be accurately controlled in temperature, and the grating spacing can be accurately adjusted.

[0056] Under the measurement environment of 20°C, when the incident wavelength is set to 6μm-11.5μm, the number of grating lines in the initial dispersion grating 4 is 38l i ne / mm, and the spectral resolution of the spectrometer is about 86nm; the heating element 5 is controlled by the control module 8 to increase the temperature in the dispersion grating 4 to 292°C, and the temperature is stabilized by the temperature control system and the control module 8. After the temperature of the dispersion grating 4 is stabilized, the grating lines in the dispersion grating 4 are detected to be about 20l i ne / mm, and the incident wavelength of 11.5μm-22μm is adopted. After the same imaging system 3 is used, the resolution of the spectrometer is about 164nm; the heating element 5 is controlled by the control module 8 to increase the temperature of the dispersion grating 4 to 429°C, and the temperature is stabilized by the temperature control system and the control module 8. After the temperature of the dispersion grating 4 is stabilized, the grating lines in the dispersion grating 4 are detected to be about 12l i ne / mm, using an incident wavelength of 11.5μm-22μm, the spectrometer resolution is about 281nm after the same imaging system 3. Therefore, it has been verified that by setting a temperature control structure, the grating lines can be accurately changed within the range of 12l ine / mm-38l i ne / mm.

[0057] Specifically, the optical window 2 is made of an optical glass sheet that can transmit infrared rays in the 6-40 micron band, and the detector is a BIB detector that can receive signals in this band, thereby achieving spectral splitting of 6-40 microns.

[0058] In summary, the present invention can meet different spectral resolution requirements without replacing the dispersion grating 4, avoids the adjustment error and the influence on the system sensitivity and signal-to-noise ratio, and can realize the spectrum splitting of the ultra-wide band of 6μm-40μm. It has a very positive significance for the application in the fields of low-temperature spectral imaging, etc., with simpler operation, higher sensitivity, and a wider range of application fields.

[0059] In other practicable embodiments, the heating element 5 and the cold chain 62 are both close to the astigmatism grating 4, and the heating element 5 is close to the grating, so that the lens and detector of the optical system are affected as little as possible by the heating element 5, and the infrared system imaging is prevented from being affected by the high temperature environment. If the heating element 5 is not close to the grating, it may affect the ambient temperature of the optical lens and detector, increase stray radiation, and bring background noise.

[0060] Moreover, by closely attaching the heating element 5 and the cold chain 62 to the dispersion grating 4, the heating efficiency can be increased and the adjustment speed can be improved. After the heating element 5 is heated and the heating is removed, compared with a grating spectrometer without a refrigeration structure, the cold chain 62 is more effective in cooling the dispersion grating 4, and the temperature of the dispersion grating 4 returns to its original state very quickly.

[0061] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A grating spectrometer, characterized in that: include: A housing (1), wherein a receiving cavity is provided in the housing (1), and an imaging structure is provided on one side of the housing (1); a dispersion grating (4), the dispersion grating (4) being arranged in the accommodating cavity, and the light emitted by the imaging structure is directed toward the dispersion grating (4); A temperature control structure, the temperature control structure comprising a heating element (5) and a cooling assembly (6), the heating element (5) being arranged in close contact with a side of the dispersion grating (4) away from the imaging structure, the cooling assembly (6) being mounted on the housing (1), and a cooling end of the cooling assembly (6) extending into the accommodating cavity.

2. The grating spectrometer according to claim 1, characterized in that: The refrigeration component (6) comprises: A refrigeration system (61), the refrigeration system (61) being installed on a side of the housing (1) away from the imaging structure, and a refrigeration end of the refrigeration system (61) extending into the accommodating cavity; A cold chain (62), one end of the cold chain (62) is connected to the refrigeration end of the refrigeration system (61), and the other end extends into the accommodating cavity.

3. The grating spectrometer according to claim 2, characterized in that: One end of the cold chain (62) away from the refrigeration system (61) is in contact with the dispersion grating (4).

4. The grating spectrometer according to claim 2, characterized in that: The temperature control structure further comprises a temperature measuring element (7), the temperature measuring end of the temperature measuring element (7) being closely attached to the side surface of the dispersion grating (4), and the temperature measuring element (7) being used to detect the temperature of the dispersion grating (4).

5. The grating spectrometer according to claim 4, characterized in that: The grating spectrometer further comprises a control module (8), wherein the control module (8) is mounted outside the housing (1); The control module (8) is also connected to the temperature measuring element (7) to receive the temperature parameter measured by the temperature measuring element (7) and control the operation of the heating element (5) and the cooling component (6) to adjust the temperature of the dispersion grating (4).

6. The grating spectrometer according to claim 1, characterized in that: The edge of the dispersion grating (4) fits in with the inner edge of the accommodating cavity.

7. The grating spectrometer according to claim 1, characterized in that: The substrate of the dispersion grating (4) is made of a substrate with a thermal expansion coefficient of 0.5×10 -6 ~1×10 -6 / k material; The periodic stripes of the dispersion grating (4) have a thermal expansion coefficient of 2.0×10 -6 ~2.5×10 -6 / k material.

8. The grating spectrometer according to claim 1, characterized in that: The imaging structure comprises: An optical window (2), the optical window (2) being opened at an end of the housing (1) away from the temperature control structure; An imaging system (3) is installed between the optical window (2) and the dispersion grating (4), and the light source is irradiated to the imaging system (3) through the optical window (2) and then directly irradiated to the dispersion grating (4).

9. The grating spectrometer according to any one of claims 1 to 8, characterized in that: The shell (1) is a vacuum dewar.

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