CN209513049U - Spectrometer dispersive elements and spectrometer - Google Patents

Abstract

The utility model discloses a kind of spectrometer dispersive elements, the dispersive elements include diffraction grating one and diffraction grating two, the diffraction grating one is near-infrared transmission diffraction grating, the diffraction grating two is near-infrared reflection diffraction grating, and the limit that the limiting resolution of the diffraction grating one is less than the diffraction grating two divides ratio.Dispersive elements are by using double grating, incident directional light successively passes through the light splitting diffraction of diffraction grating one and diffraction grating two, can have stronger diffracting power, realizes more accurate wavelength measurement, to make spectrometer for the broadband light of bigger wave-length coverage, possess higher light splitting ability.

Description

Spectrometer Dispersion Components and Spectrometers

technical field

The utility model relates to the technical field of spectrum detection, in particular to a spectrometer dispersion component and a spectrometer.

Background technique

Imaging spectrometer is one of the main instruments used for target detection, identification and material composition analysis. It can obtain the geometric feature distribution and spectral feature information of the target at the same time, and is widely used in geological survey, environmental monitoring, agricultural and forestry economics, and scientific research.

The spectroscopic function of the imaging spectrometer is realized by the spectroscopic device, which directly affects performance parameters such as the resolution of the spectrometer. Spectroscopic devices are usually composed of gratings, prisms, or grating-prisms, each with its own advantages.

The patent document CN201810184071.X "A Prism-Type Spatial Heterodyne Spectrometer" and CN201711251506.X "A Double Grating Co-CCD Spectrometer" mentioned in the spectrometer structure device that uses two dispersion elements to split the broadband light twice, Among them, the dispersion system mentioned in "A Double Grating Co-CCD Spectrometer" is two gratings. The function of the dispersion group in its device system is mainly to perform dispersion and splitting of the two spectral ranges. For the same light source The demand for high-resolution imaging with broadband light cannot be met. The dispersion system mentioned in the patent document "A Prism-Type Spatial Heterodyne Spectrometer" is two prisms. The system has ultra-high resolution and is suitable for detecting atmospheric remote sensing, astronomical observation and other fields. However, the space heterodyne spectrometer itself is a For an interference system, for complex coherent light, its internal interference signal becomes complex, and the dynamic range, precision, and system performance of its detector will be limited.

Contents of the invention

In order to solve the deficiencies in the prior art, the utility model provides a spectrometer dispersion component and a spectrometer.

The solution to solve its technical problem is: a spectrometer dispersion component, the dispersion component includes a diffraction grating one and a diffraction grating two, the diffraction grating one is a near-infrared transmissive diffraction grating, and the diffraction grating two is a near-infrared reflection grating diffraction grating, the limiting resolution of the first diffraction grating is smaller than the limiting resolution of the second diffraction grating.

Further, the first diffraction grating is a near-infrared transmissive diffraction grating with 300 rule pairs; the second diffraction grating is a near-infrared reflective diffraction grating with 1800 rule pairs.

Further, the dimensions of the first diffraction grating and the second diffraction grating are 20mm×20mm-30mm×30mm.

Another aspect of the utility model also provides a spectrometer comprising the above-mentioned dispersion component.

Further, the above-mentioned spectrometer also includes an optical fiber access module, a light focusing module, and a detector module.

Further, the above fiber access module includes a fiber access slit and a fiber collimator.

Further, the above optical focusing module is an achromatic focusing cylindrical lens.

Further, the focal length of the achromatic focusing cylindrical lens is 30-70mm.

Further, the above-mentioned detector module is a linear array CCD.

Further, the above linear CCD has 4096 pixels.

The beneficial effects of the utility model are: the dispersion component of the utility model can have stronger diffraction power by adopting double gratings, and realize more accurate wavelength measurement, so that the spectrometer has higher Spectroscopy.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following will briefly describe the accompanying drawings that are used in the description of the embodiments. Apparently, the drawings described are only some embodiments of the utility model, not all embodiments, and those skilled in the art can also obtain other designs and drawings according to these drawings without creative work.

Fig. 1 is a schematic diagram of a dispersion component provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a spectrometer provided by an embodiment of the present invention.

Detailed ways

The idea, specific structure and technical effects of the present utility model will be clearly and completely described below in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, characteristics and effects of the present utility model. Apparently, the described embodiments are only some of the embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, other embodiments obtained by those skilled in the art without paying creative efforts, All belong to the protection scope of the utility model. Each technical feature in the invention of the utility model can be combined interactively under the premise of not conflicting with each other.

A grating is a common spectroscopic element. When a parallel monochromatic beam is irradiated on the grating, it will produce different orders of diffraction. When a parallel polychromatic beam is irradiated on the grating, it will cause dispersion, so that different wavelengths can satisfy the grating equation.

With reference to Fig. 1, the spectrometer dispersion assembly of the present utility model comprises diffraction grating one 3 and diffraction grating two 4, and diffraction grating one 3 is near-infrared transmissive diffraction grating, and diffraction grating two 4 is near-infrared reflective diffraction grating, and diffraction grating one The limit resolution of 3 is smaller than the limit ratio of diffraction grating 2 4.

The diffraction angle of each output light is a linear distribution of the wavelength. Since the optical resolution of the diffraction grating 13 is smaller than that of the diffraction grating 2, for broadband light, it can continuously pass through the diffraction grating 1 3 and the diffraction grating 2 4 to achieve high-resolution light splitting .

In one embodiment, the first diffraction grating 3 is a near-infrared transmissive diffraction grating with 300 rule pairs; the second diffraction grating 4 is a near-infrared reflective diffraction grating with 1800 rule pairs.

The limiting resolution of the grating: Δλ=λ/(mN), where λ wavelength, m order, and the number of lines covered by N beams on the grating. Therefore, under the same conditions, the more reticle pairs, the higher the grating resolution.

Specifically, for the dispersion component of this embodiment, the collimated parallel light first passes through a near-infrared transmissive diffraction grating-3 with 300 reticle pairs, is incident on the grating surface at a grating blaze angle, and diverges at a fixed angle, taking a order diffraction, the diffraction angle corresponding to the wavelength can be calculated according to the grating equation, that is, the diffraction angle θ _i can be expressed as: Where λ represents the wavelength and d is the grating length. Its theoretical light difference resolution is defined as: where N is the number of dents irradiated and m is the diffraction order, so that an approximation of the theoretical value of the post-collimated beam diameter can be calculated. Next, each ray of light from the first-order diffraction of the diffraction grating 1 3 will enter at a fixed diffraction angle θ _i . When the light enters the diffraction grating 2 4 in a certain direction, its grating expression is: a[sin( θ _m )-sin(θ _i )]=mλ. Where a is 1/1800, the optical difference resolution of the broadband light after passing through the second-level grating will increase, and a spectral dispersion diffraction pattern with a super large diffraction angle will be realized.

The dimensions of the first diffraction grating 3 and the second diffraction grating 4 are usually 20mm×20mm-30mm×30mm, such as 25mm×25mm, 20mm×20mm and so on.

Referring to FIG. 2 , it is a schematic structural diagram of a spectrometer including the dispersion component of the present invention, which includes an optical fiber access module, a dispersion component, an optical focusing module 5, and a detector 6 in sequence.

Wherein, the fiber access module includes a fiber access slit 1 and a fiber collimator 2 . The dispersion module includes a diffraction grating 1 3 and a diffraction grating 2 4, and the parameters of the two gratings are respectively: a near-infrared transmissive diffraction grating with 300 reticle pairs and a near-infrared reflective diffraction grating with 1800 reticle pairs in the size of 25 mm x 25 mm raster.

The incident broadband light from the fiber optic slit 1 is first collimated by the fiber collimator 2, and the incident divergent light is collimated into parallel light. The parallel light first passes through the diffraction grating 3 with 300 reticle pairs, and then, each different wavelength The light will be emitted at a fixed diffraction angle, and then enter the diffraction grating 4 with 1800 reticle pairs. After the light passes through the two gratings, high-precision light splitting in the same direction will be realized. on detector 6.

The optical focusing module 5 can be an achromatic focusing cylindrical lens. Preferably, the focal length of the achromatic focusing cylindrical lens is 30-70mm, such as 30mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, etc.

The detector 6 may be a linear CCD, preferably, the linear CCD has 4096 pixels.

Further, the signal received by the detector 6 can be transmitted to a computer for imaging.

In summary, the dispersion component of the present invention adopts double gratings, and the incident parallel light passes through the first diffraction grating and the second diffraction grating in turn, so that it can have stronger diffraction power and achieve more accurate wavelength measurement, so that the spectrometer can be used for Broadband light with a larger wavelength range has higher spectral power.

The preferred embodiments of the present utility model have been specifically described above, but the present invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent modifications or replacements without violating the spirit of the present invention. , these equivalent modifications or replacements are all included within the scope defined by the claims of the present application.

Claims (10)

1. a kind of spectrometer dispersive elements, it is characterised in that: the dispersive elements include diffraction grating one and diffraction grating two, institute Stating diffraction grating one is near-infrared transmission diffraction grating, and the diffraction grating two is near-infrared reflection diffraction grating, described The limit that the limiting resolution of diffraction grating one is less than the diffraction grating two divides ratio.

2. dispersive elements according to claim 1, which is characterized in that the diffraction grating one is the close red of 300 grooves pair Outer transmittance diffraction grating；The diffraction grating two is the near-infrared reflection diffraction grating of 1800 grooves pair.

3. dispersive elements according to claim 1 or 2, which is characterized in that the diffraction grating one and diffraction grating two Having a size of 20mm × 20mm -30mm × 30mm.

4. a kind of spectrometer, which is characterized in that including dispersive elements as described in any one of claims 1-3.

5. spectrometer according to claim 4, which is characterized in that further include intelligent acess module, light focus module, detection Device module.

6. spectrometer according to claim 5, which is characterized in that the intelligent acess module includes intelligent acess slit, Optical fiber collimator.

7. spectrometer according to claim 5, which is characterized in that the smooth focus module is achromatism focal lens.

8. spectrometer according to claim 7, which is characterized in that the focal length of the achromatism focal lens is 30- 70mm。

9. spectrometer according to claim 5, which is characterized in that detector module is line array CCD.

10. spectrometer according to claim 9, which is characterized in that the pixel of the line array CCD is 4096.