Volume holographic optical grating type spatial heterodyne Raman imaging spectrograph light path structure

Abstract

The invention provides a volume holographic optical grating type spatial heterodyne Raman imaging spectrograph light path structure. The imaging spectrograph comprises a carrying stage, a first collimating lens, a first Raman light filter, a first reflector, a first focusing lens, a first beam splitting plate, a second beam splitting plate, two second reflectors, two volume holographic grisms, a second Raman light filter, a second collimating lens, a third reflector, a second focusing lens, an exit pupil, a field lens and an area-array detector. The volume holographic optical grating type spatial heterodyne Raman imaging spectrograph proposed by the invention combines the advantages of a dispersion type Raman spectrograph and a Fourier transform Raman spectrometer. According to the spectrograph of the invention, the beam splitting plates are adopted to split a light path into two arm light paths, so that spatial heterodyne Raman interference light can be obtained; the spatial heterodyne interference light is utilized to obtain imaging spectrum information; the volume holographic grisms are adopted to improve the luminous flux of the system and increase the field of view of the system. The spectrograph light path structure of the invention has the advantages of compact overall structure, no moving parts, stable performance and high reliability.

Description

technical field [0001] The invention relates to the technical field of spectral analysis instruments, in particular to an optical path structure of a volume holographic grating type spatial heterodyne Raman imaging spectrometer. Background technique [0002] Raman spectroscopy is a non-destructive detection method based on the characteristics of light-matter interaction using inelastic Raman light scattering. The incident laser excites the measured molecular system, thereby generating Raman scattered light with a frequency different from that of the incident light. By measuring the relative intensity of a specific spectral component in the Raman scattering spectrum and its frequency shift relative to the incident light, the relevant information of the measured molecular system can be obtained. However, some chemical substances have similar Raman spectral features, which require high-resolution Raman spectrometers to distinguish them. According to the working principle of R...

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Problems solved by technology

The dispersive Raman spectrometer needs a very small slit to obtain high resolution, so the dispersive Raman spectrometer cannot obtain high luminous flux; the Fourier transform Raman spectrometer does not require an incident slit and can achieve high resolution High-efficiency and high-throughput characteristics, but this kind of spectrometer needs to use moving parts to obtain optical path difference; tunable filter Raman spectrometer has the advantages of no moving firmware and small size, but its resolution is low and it cannot work in the ultraviolet band

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