Low-noise spatial heterodyne spectrometer for short-wave ultraviolet Raman spectrum detection

Abstract

The invention discloses a low-noise spatial heterodyne spectrometer for short-wave ultraviolet Raman spectrum detection. The low-noise spatial heterodyne spectrometer comprises a front objective lens,a Raman light filter, a beam splitter with a diaphragm, a first collimating objective lens, a first reflecting grating, a second collimating objective lens, a second reflecting grating, a third collimating objective lens and an area-array camera. The first collimating objective lens and the third collimating objective lens form a 4f system, and the second collimating objective lens and the thirdcollimating objective lens form a 4f system; and after diffraction spectrum signals reflected by the first grating and the second grating pass through the beam splitter with the diaphragm, only spectrum signals with effective diffraction orders enter the area-array camera. According to the low-noise spatial heterodyne spectrometer for short-wave ultraviolet Raman spectrum detection, useless straylight of the grating can be effectively suppressed, and the signal-to-noise ratio and sensitivity of short-wave ultraviolet Raman spectrum detection are improved.

Description

technical field [0001] The invention relates to the field of optical imaging, in particular to a low-noise spatial heterodyne spectrometer for short-wave ultraviolet Raman spectrum detection. Background technique [0002] Raman spectroscopy reflects the internal structure and state characteristics of molecules, has a "fingerprint" effect, and is an important means of analyzing the structure of organic compounds. It has important application value in the fields of biomedicine, chemical analysis, pollutant monitoring and so on. [0003] Spatial heterodyne Raman spectrometer has limitations such as high throughput, wide field of view, and compact structure. It is an important Raman spectroscopy test method developed in recent years. Short-wave ultraviolet Raman spectroscopy has the advantages of high excitation efficiency, weak fluorescence signal, low background noise, and enhanced resonance. It is one of the important development directions of Raman spectroscopy. However, w...

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Problems solved by technology

However, when detecting the short-wave ultraviolet spectrum (200nm-300nm), the wavelength is only 1 / 3-1 / 2 of the visible and near-infrared light, so that the invalid diffraction orders of the grating are multiplied, and the angle between adjacent diffraction orders is reduced. This increases the stray light of the system and reduces the detection sensitivity of the system. At the same time, spectral false peaks may appear, which affects the accuracy of Raman spectrum detection.

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