Dehghany M, Michaelian K H
Natural Resources Canada, CanmetENERGY-Devon, 1 Oil Patch Drive, Suite A202, Devon, Alberta T9G 1A8, Canada.
Rev Sci Instrum. 2012 Jun;83(6):064901. doi: 10.1063/1.4727877.
Quantum cascade laser-based instrumentation for dual beam photoacoustic (PA) spectroscopy is described in this article. Experimental equipment includes a 4.55 μm (2141-2265 cm(-1)) continuous wave external cavity quantum cascade laser (EC-QCL), two gas-microphone PA cells, and two lock-in amplifiers. Correction for the time and wavenumber dependence of the laser output is effected through real-time division of the PA signals derived from the sample and reference channels. Source-compensated mid-infrared absorption spectra of carbon black powder and aromatic hydrocarbon solids were obtained to confirm the reliability of the method. Absorption maxima in the EC-QCL PA spectra of hydrocarbons are better defined than those in Fourier transform infrared spectra acquired under similar conditions, enabling the detection of several previously unknown bands.
本文介绍了基于量子级联激光器的双光束光声（PA）光谱仪。实验设备包括一台4.55μm（2141 - 2265cm⁻¹）连续波外腔量子级联激光器（EC-QCL）、两个气体麦克风光声池和两个锁相放大器。通过对来自样品和参考通道的光声信号进行实时除法运算，实现对激光输出的时间和波数依赖性的校正。获得了炭黑粉末和芳烃固体的源补偿中红外吸收光谱，以确认该方法的可靠性。与在类似条件下获得的傅里叶变换红外光谱相比，烃类的EC-QCL光声光谱中的吸收最大值定义得更好，从而能够检测到几个以前未知的谱带。
