TABLE OF CONTENTS The large number of investigations using powerful solid-state lasers in superhigh resolution spectroscopy in the selective ionisation and excitation of atoms and molecules, plasma diagnostics and beams of atoms and ions, etc., imposes more and more stringent requirements on the laser radiation parameters: power, the width of the spectrum and its tuning, the time and spatial distribution of intensity, the stability of the spectrum and the time of appearance of the pulse. The solid-state lasers with Q-factor modulation (active and passive) in the giant pulse regime are used widely in various areas of science, investigations and technology.
In lasers with the passive Q-factor modulation of the resonator ( Q-modulation), the efficiency of selection of longitudinal modes is considerably higher than in lasers with active Q-modulation. This is determined by the fact that in the lasers with passive Q-modulation, the duration of the linear development of the giant pulse is approximately 1 microsecond, whereas in the lasers with active Q-modulation, it is an order of magnitude shorter.
During linear development, various modes increase from the level of spontaneous noise independently of each other, and the ratio of the amplitude of the modes at the moment of non-linear development of the giant pulse determines the modes that are included in lasing. In the case of passive Q-modulation, the number of passages of photons through the resonator is of the order of 1000. Consequently, the necessary...
