Kapitanov V A, Ponomarev Yu N, Tyryshkin I S, Rostov A P
Institute of Atmospheric Optics, SB RAS, 1 Akademicheskii Avenue, 634055 Tomsk, Russia.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Apr;66(4-5):811-8. doi: 10.1016/j.saa.2006.10.046. Epub 2006 Nov 6.
We describe the hardware and software of the high-sensitive two-channel opto-acoustic spectrometer with a near infrared diode laser. A semiconductor TEC-100 laser with outer resonator generates a continuous single-frequency radiation in the range of 6040-6300 cm-1 with spectral resolution better that 10 MHz. The newly designed model of photo-acoustic cells in the form of a ring type resonator was used in the spectrometer, and the system allows the measurement of a weak absorption coefficient equal to 1.4x10(-7) cm-1 Hz-1/2 with a laser radiation power of 0.003 W. The methane absorption spectra within a range of 6080-6180 cm-1 were measured with a spectral resolution of 10 MHz and the signal to noise ratio more than 10(3). Six hundred absorption lines were recorded, which is twice as many as in HITRAN-2004. The accurate measurements of the half-width and shift of methane unresolved triplet R3 of 2nu3 band permit us to determine values of the broadening and shift coefficients for CH4-air, CH4-N2, and CH4-SF6 mixtures.
我们描述了带有近红外二极管激光器的高灵敏度双通道光声光谱仪的硬件和软件。带有外腔的半导体TEC - 100激光器在6040 - 6300 cm⁻¹范围内产生连续单频辐射，光谱分辨率优于10 MHz。光谱仪采用了新设计的环形谐振器形式的光声池模型，该系统在激光辐射功率为0.003 W时，能够测量低至1.4×10⁻⁷ cm⁻¹ Hz⁻¹/²的弱吸收系数。在6080 - 6180 cm⁻¹范围内测量了甲烷吸收光谱，光谱分辨率为10 MHz，信噪比大于10³。记录了600条吸收线，这是HITRAN - 2004中吸收线数量的两倍。对2ν₃带甲烷未分辨三重态R3的半高宽和频移的精确测量，使我们能够确定CH₄ - 空气、CH₄ - N₂和CH₄ - SF₆混合物的展宽系数和频移系数值。
