Characteristics of the kinetics of the spectral distribution of laser radiation in investigations of transient absorption by intracavity laser spectroscopy

An investigation was made of the establishment of a spectral distribution of neodymium laser radiation in intracavity laser spectroscopy. The kinetics of the spectral distribution was studied at the moments of switching on and off frequency-dependent losses in the resonator. The transient losses inside the resonator were due to the absorption from excited electronic levels of the nitrogen molecule in an electric discharge. Lines representing excited nitrogen and acetylene dissociation products were amplified. A "memory" of the spectral distribution of the laser radiation was predicted theoretically and confirmed experimentally. The results demonstrated that intracavity laser spectroscopy was a suitable method for investigating transient absorption processes if allowance was made for the special features of the establishment of a spectral distribution. The lifetime of excited nitrogen atoms was estimated.