Quantitative analysis of decay transients applied to a multimode pulsed cavity ringdown experiment.

Area of Science:

• Spectroscopy
• Physical Chemistry
• Optical Physics

Background:

• Cavity Ringdown Spectroscopy (CRS) is a powerful technique for measuring light absorption.
• Analysis of decay transients in CRS can be affected by baseline offsets, leading to inaccurate decay rate estimations.
• Achieving monoexponential decays is crucial for accurate analysis, especially under multimode excitation.

Purpose of the Study:

• To analyze the intensity and noise properties of decay transients in a generic pulsed cavity ringdown experiment.
• To develop and validate a robust method for estimating decay rates and their precision.
• To establish an on-line alignment method for optical resonators to achieve monoexponential decays.

Main Methods:

• Experimental and theoretical analysis of decay transients from pulsed cavity ringdown.
• Application of a weighted nonlinear least-squares analysis to digitized decay transients.
• Development of an on-line method based on statistical noise analysis for resonator alignment.

Main Results:

• The weighted nonlinear least-squares analysis effectively avoids baseline offset errors in decay rate estimation.
• Simulations confirm that the method provides accurate estimates for fit parameters and their precision.
• Experimental demonstration of achieving monoexponential decays in a stable optical resonator under multimode excitation.

Conclusions:

• The developed analysis method offers accurate and precise determination of decay rates in cavity ringdown spectroscopy.
• The on-line alignment technique facilitates the achievement of monoexponential decays, enhancing measurement reliability.
• This work improves the accuracy and efficiency of pulsed cavity ringdown experiments.