Optimized extraction of ring-down time in cavity ring-down spectroscopy

Searching an efficient algorithm for extracting ring-down time in cavity ring-down spectroscopy (CRDS) is very important. Two kinds of simulated ring-down signals with Gaussian white noises were analyzed using Levenberg-Marquardt (L-M) algorithm and least squares (LS) method, nd the results show that L-M algorithm gives better results, smaller relative error, higher noises immunity and better repetition than LS method. Two kinds of CRDS setups were founded to produce CW and pulsed ring-down signals, experimental data were processed according to theoretical analyses. Experimental results are consistent with the simulated ones.