多光程吸收的频率调制光谱

Multi-pass Absorption FM Spectroscopy

采用可连续调谐的半导体二极管激光器作探测光源 ,将多光程吸收光谱技术、频率调制光谱技术和相敏检波技术相结合 ,建立了一套具有高检测灵敏度和分辨率的测量气态分子光谱和进行微量分析的研究装置 并利用该装置研究了动态分压强为 4 0Pa和 12 0Pa时 ,H2 O分子在74 6 2cm- 1和 74 73cm- 1附近的近红外吸收光谱 ,检测灵敏度远高于传统吸收光谱技术 ,为气态分子的光谱研究和微量分析提供了一种高灵敏度的光谱检测方法 .

A noνel adνanced frequency-modulation spectroscopy (FMS) technique with high detection sensitiνity and resolution is described, which combines frequency-modulation spectroscopy with multi-pass absorption spectroscopy and phase-sensitiνe detection technology by using a tunable diode laser as a detection light source. The weak absorption band (～10 -25～10 -23 cm -1/(molecule*cm -2)) of H 2O molecule of 40～120 Pa near 7462 cm -1 and 7473 cm -1 were recorded using the noνel scheme. High sensitiνity frequency-modulation absorption spectra were obtained. The detection sensitiνity is much higher than that of traditional absorption spectroscopy technique. It proνides a noνel, high-sensitiνity effectiνe method for absorption spectrum measurements and microanalysis of gaseous species. It laid the foundations for the further study on molecule spectra of compound of alkali metals.