亞多普勒波長調(diào)制NICE-OHMS疊加光譜干擾抑制

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Suppression of overlapping spectral interference based on sub-Doppler wavelength modulation NICE-OHMS

（1. State Key Laboratory of Quantum Optics Technologies and Devices ， Institute ofLaser Spectroscopy，Shanxi University，Taiyuan O3OoO6，China; 2. Collaborative Innovation Center of Extreme Optics， Shanxi University， Taiyuan O3ooo6，China; 3. Collegel ofPhysics and Electronic Engineering， Shanxi University， Taiyuan O3OoO6， China） * Corresponding author， E -mail： gang-zhao@sxu. edu. cn;mwg@sxu. edu. cn

Abstract： To mitigate the impact of overlapping spectra on the accuracy of spectral information extraction，a multi-gas spectral detection method is proposed in this study，based on Sub-Doppler Noise-Immune Cavity-Enhanced Optical Heterodyne Molecular Spectroscopy （NICE-OHMS）. This method lever ages high laser power excitation saturation absorption established within a high-finesse optical cavity，resultingin a significant enhancement in spectral resolution and a reduction in spectral interference caused by impurity gases. Furthermore，the incorporation of wavelength modulation techniques effectively eliminates the influence of residual Doppler background on the sub-Doppler signal. A wavelength-modulated sub-Doppler NICE-OHMS model has been developed，with experimental investigations conducted using the transition lines of C2H2 and NH3 at 1531nm . The results demonstrate that，under conditions of a modulation frequency of 150Hz and a modulation amplitude of 2.68MHz ，a sub-Doppler absorption signal of C2H2 exhibiting a saturation degree of 12.1O can be successfully excited within the optical cavity. Additionally，the sub-Doppler absorptionof C2H2 isunaffected by the adjacent NH3 spectra and the Doppler background. The sensitivity of the detection system is determined to be 1.163×10-12cm-1 via Allan variance analysis.These findings confirm that this technique efectively eliminates spectral interference from impurity gases while maintaining high sensitivity and selectivity within the spectral system.

rds： laser absorption spectroscopy；Noise-Immune Cavity-Enhanced Optical Heterodyne Molecu lar Spectroscopy（NICE-OHMS）； sub-Doppler; overlapping spectral

1引言

激光吸收光譜（LaserAbsorption Spectroscopy，LAS）技術(shù)因其高靈敏度、高選擇性和高精度等優(yōu)勢(shì)，在痕量氣體分析中得到了廣泛應(yīng)用，涉及工農(nóng)業(yè)生產(chǎn)[2-4]、健康預(yù)防[5]、高精尖產(chǎn)業(yè)[6]以及科學(xué)探索[7-8]等領(lǐng)域。（剩余18724字）