采用扫描谐振腔进行腔内振铃红外吸收光谱研究

提出了一种新型的连续激光振铃吸收光谱方法，采用由高反射率腔镜组成的谐振腔作气体吸收池，通过压电晶体对谐振腔以4Hz频率进行扫描调制，对连续波激发光源在一定光谱范围内以0．001Hz的低重复频率进行同步光谱扫描，让振铃腔与激光频率形成共振．通过探测腔模的透射峰光强，获得光谱信息．采用该技术在0．5mbar的极低气压下，探测到CO2在6537cm^-1和6577cm^-1附近的弱吸收谱线(10^-27.10^26cm^-1／(molecute．cm^-2)，其检测灵敏度远高于常规红外吸收光谱方法，为气态原子、分子和离子的微量探测提供了高灵敏度的光谱分析方法。

High Sensitivity Continuous-wave Cavity Ring-Down Infrared Spectroscopy Based on a Rapidly Swept Cavity

A novel advanced approach to continuous-wave cavity ring-down spectroscopy (CW-CRDS) based on a rapidly swept cavity is described, in which an optical cavity with super-high reflectivity cavity mirrors is used as a gaseous species pool of absorption spectra. The cavity is swept by PZT at 4 Hz repetition rate to shift the frequency of optical radiation stored in the cavity. A continuous-wave tunable diode laser frequency is synchronously scanned over a small range (-1 cm-1) at a low repetition rate. The transmitted cavity mode peaks are recorded. Absorption spectrum data is extracted from the envelope of the transmitted cavity mode peaks. High sensitivity absorption spectra of low CO2 content of 0.5 mbar near 6537 cm-1 and the weak absorption band (-10-27 cm-1/(molecule- cm-2)) near 6577 cm-1 were recorded using the novel scheme. The detection sensitivity is much higher than that of traditional absorption spectroscopy technique. It provides a novel, high-sensitivity, effective method for absorption spectrum measurements and microanalysis of gaseous species.