Precision of single‐shot dual‐broadband rotational CARS thermometry with single‐mode and multi‐mode Nd:YAG lasers

Abstract

AbstractThe precision of single‐shot coherent anti‐Stokes Raman spectroscopy (CARS) thermometry is an important characteristic for the application of CARS in various combustion devices such as internal combustion engines. It is generally assumed that the precision of CARS is directly related to the spectral noise of the interacting laser fields, and previous studies have presented a theoretical model describing the behaviour of the noise as a function of various experimental parameters. In this work, the aim was to test the results predicted by the previously developed model for dual‐broadband rotational CARS. We studied the precision of evaluated temperatures in pure nitrogen under different experimental conditions, namely the dependence of precision on the gas pressure and on the linewidth of the narrowband laser (the Nd:YAG laser). It was demonstrated that our experiments reproduce the main features of the model, and that a single‐mode Nd:YAG laser leads to better precision than a multi‐mode Nd:YAG laser for dual‐broadband rotational CARS thermometry. Copyright © 2003 John Wiley & Sons, Ltd.