Theoretical analysis on the dynamic absorption saturation in pulsed cavity ringdown spectroscopy
Theoretical analysis on the dynamic absorption saturation in pulsed cavity ringdown spectroscopy
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DOI：
10.1007/s00340-004-1583-6
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发表时间：
2004-09-01
影响因子：
2.1
通讯作者：
Hahn, JW
中科院分区：
文献类型：
--
作者：
Lee, JY;Hahn, JW
我们对脉冲腔衰荡光谱中吸收饱和的瞬态动力学进行了理论分析。基于耦合速率方程方法，对动态饱和度进行建模，以考虑随时间演化的腔内光子密度和吸收布居。主方程是根据归一化系统参数导出的，这使得人们能够系统地研究饱和腔衰荡信号的非指数特征。对传统振铃时间分析对样品吸光度的错误量化进行了数值模拟，并且获得了多普勒展宽样品的显示兰姆倾角的饱和光谱特征。最后，提出了一种新的数值方法来处理饱和衰荡信号并检索不饱和光谱，允许相关吸收参数而不降低测量信噪比。
We perform a theoretical analysis on the transient dynamics of absorption saturation in pulsed cavity ringdown spectroscopy. Based on a coupled rate equation approach, modelling of the dynamic saturation is carried out to account for time-evolving intracavity photon density and absorbing population. Master equations are derived in terms of normalized system parameters, which enables one to systematically study the non-exponential feature of saturated cavity ringdown signals. Erroneous quantification of sample absorbance by the conventional ringdown time analysis is numerically simulated, and the saturated spectral feature showing a Lamb dip is obtained for a Doppler broadened sample. Finally a novel numerical recipe is proposed to handle saturated ringdown signals and retrieve unsaturated spectra, allowing relevant absorption parameters without degrading the measurement signal-to-noise ratio.