Control of the pulse duration in one- and two-axis passively Q-switched solid-state lasers
Laboratoire d'Électronique Quantique-Physique des Lasers (UMR 6627 du CNRS) , Université de Rennes I, Campus de Beaulieu, 35042 Rennes Cedex, France
Corresponding author: a email@example.com
Published online: 15 June 2002
We study theoretically and experimentally different methods to control the pulses emitted by solid-state lasers passively Q-switched by a saturable absorber. We explore one- and two-axis laser schemes allowing to control the pulse duration, which is ruled by the saturation powers of the transitions in the absorber and in the gain medium. In one-axis lasers, it is shown that the adjustment of the pump and laser beam sizes in the active medium and in the absorber provides an efficient means to control the pulse temporal shape and duration. Furthermore, a two-axis laser cavity supporting so-called forked-eigenstate operation permits to freely adjust the parts of the mode power which circulate in the gain medium and in the absorber. In this case, a lengthening of the pulse duration up to 500 ns is obtained with an increase of the average output power. The theoretical results obtained by using rate equations adapted to each cavity geometry are in close agreement with experiments performed on a diode-pumped Nd3+:YAG laser Q-switched by a Cr4+:YAG saturable absorber. The relevance of the different techniques to control the pulse durations in the framework of potential applications is discussed.
PACS: 42.55.Ah – General laser theory / 42.60.Gd – Q-switching / 42.55.Rz – Doped-insulator lasers and other solid state lasers
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002