Frequency-locked v-type enhancement cavity for signal enhancement in gas Raman spectroscopy

Abstract

The invention discloses a frequency-locking V-type strengthening chamber for strengthening Raman spectrum detection signals of gases. The frequency-locking V-type strengthening chamber comprises a laser unit, a V-type strengthening chamber unit and a frequency locking unit. The laser unit comprises a laser device, a current controller and a signal generator. The V-type strengthening chamber unit comprises three high-transmittance high-reflectance lenses in V-shaped arrangement. Laser enters the strengthening chamber from M4, and is reflected back and forth for over ten thousands of times among the M4, M5 and M6. The frequency locking unit comprises a detector A, a detector B, a PZT (piezoe-lectric transducer) and a data collection card. The detector A collects chamber-front power signals, the detector B collets chamber-back power signals, and channel-2 signals enter a computer via the data collection card. The computer analyzes change conditions of specific values of the chamber-front signals and the chamber-back signals, and outputs PZT feedback control signals to adjust the position of the PZT, so that phase matching of feedback laser is achieved, and effective locking of output frequency of the laser device is also realized. By the frequency-locking V-type strengthening chamber, strengthening of Raman spectrum scattering signals of trace gases is realized.

Description

technical field [0001] The invention relates to the field of gas detection in industries such as environment and electric power, and in particular relates to a frequency-locked V-shaped enhancement cavity for enhancing gas Raman spectrum detection signals. Background technique [0002] Gas detection technology and equipment are necessary and important detection methods in the fields of industrial production process control, environmental monitoring, early fault diagnosis of power transformers, and national security. There are many types of mixed gases that need to be detected and the concentration is usually on the order of ppm or ppb. Currently commonly used gas chromatography, mass spectrometry, semiconductor gas sensor method, infrared absorption spectroscopy, and photoacoustic spectroscopy have problems such as the need to replace the chromatographic column, cross-sensitivity of mixed gases, easy aging, and low stability, which cannot meet the needs of trace gases in vari...

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Problems solved by technology

Aiming at the current situation that the gas Raman scattering cross-sectional area is small and the Raman scattering effect is weak, so that the minimum detection concentration based on Raman spectrum analysis cannot meet the requirements of trace characteristic gas detection, the invention proposes a method for enhancing the gas Raman spectrum detection signal Frequency-locked V-shaped enhancement cavity, based on multi-beam interference and laser output frequency locking enhancement cavity mode, so that the laser is efficiently coupled into the enhancement cavity and reflected back and forth multiple times in the cavity, while improving the effective length of laser and gas and laser power, greatly Increased Gas Raman Scattering Intensity

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