System for removing Raman spectral scattering background noise

Abstract

The invention discloses a system and a method which are based on a vibrating charger and cooperate with a lock phase amplifier to remove the background noise produced by a capillary tube and the like in gas Raman scattering. The invention includes a vibrator and a lock phase amplification method. The vibration generated by the vibrator drives the gas in the glass capillary tube to produce tiny waves, consequently, the number of gas molecules in the capillary tube is changed, and a gas molecule Raman scattering signal which is fluctuated at fixed frequency is obtained. By means of the reference frequency provided by a signal generator, the lock phase amplifier extracts the gas molecule Raman scattering signal fluctuated at the frequency from a total Raman scattering signal. The invention overcomes the affection of background scattering noise on a measuring result in the process of Raman gas analysis and testing, and solves the defect that various systems cannot thoroughly remove background noise. The gas Raman scattering detection system provided by the invention has a simple structure, is convenient to operate, and is highly practical.

Description

Technical field [0001] The invention belongs to the technical field of optical measurement, and relates to a system for removing Raman spectrum scattering background noise. The device is particularly suitable for removing Raman scattering background noise generated by capillary tubes and the like in a Raman scattering device. Background technique [0002] Raman scattering is a kind of inelastic scattering of photons, that is, after a beam of monochromatic light is scattered by a medium, it produces a new physical phenomenon of light radiation with a frequency different from the incident light. The scattered light is relative to the pump light. The frequency shift corresponds to the energy difference between the rotation, vibration or electronic energy level of the molecule / atom, so the composition of the scatterer can be determined by the Raman frequency shift. Raman scattering has been widely used in material composition analysis, medical monitoring, and air pollution detection....

AI Technical Summary

Problems solved by technology

However, due to the Raman scattering noise generated by the glass wall of the capillary, it will inevitably enter the hollow area of ​​the capillary, inevitably forming a continuous background scattering spectrum

In addition, the group also proposed to replace the glass capillary with a metal-coated polycarbonate capillary. Since polycarbonate has a small Raman scattering cross-section, the background Raman scattering noise is greatly reduced, but this method cannot completely eliminate the capillary glass wall. Raman scattering background

Bortnik et al. also proposed the use of metal capillaries to replace glass capillaries. Metal capillaries can greatly reduce the background and be used in some special environments such as space exploration applications, but their high cost is not conducive to industrial applications.

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