Boyson T K, Spence T G, Calzada M E, Harb C C
School of Engineering and Information Technology, University College, The University of New South Wales, Canberra, ACT, Australia.
Opt Express. 2011 Apr 25;19(9):8092-101. doi: 10.1364/OE.19.008092.
In this paper we report on the development of a Fourier-transform based signal processing method for laser-locked Continuous Wave Cavity Ringdown Spectroscopy (CWCRDS). Rather than analysing single ringdowns, as is the norm in traditional methods, we amplitude modulate the incident light, and analyse the entire waveform output of the optical cavity; our method has more in common with Cavity Attenuated Phase Shift Spectroscopy than with traditional data analysis methods. We have compared our method to Levenburg-Marquardt non linear least squares fitting, and have found that, for signals with a noise level typical of that from a locked CWCRDS instrument, our method has a comparable accuracy and comparable or higher precision. Moreover, the analysis time is approximately 500 times faster (normalised to the same number of time domain points). Our method allows us to analyse any number of periods of the ringdown waveform at once: this allows the method to be optimised for speed and precision for a given spectrometer.
在本文中，我们报告了一种基于傅里叶变换的信号处理方法的开发，用于激光锁定连续波腔衰荡光谱（CWCRDS）。与传统方法通常分析单个衰荡不同，我们对入射光进行幅度调制，并分析光腔的整个波形输出；我们的方法与腔衰荡相移光谱的共同点比与传统数据分析方法更多。我们已将我们的方法与列文伯格 - 马夸尔特非线性最小二乘法拟合进行了比较，并且发现，对于具有锁定CWCRDS仪器典型噪声水平的信号，我们的方法具有相当的准确度以及相当或更高的精度。此外，分析时间快约500倍（归一化为相同数量的时域点）。我们的方法允许我们一次分析任意数量的衰荡波形周期：这使得该方法能够针对给定的光谱仪在速度和精度方面进行优化。
