Generation of extended pulse trains of minimum duration by passive negative feedback applied to solid-state Q-switched lasers

Abstract

Intracavity self-focusing in a thin two-photon absorber acts, in combination with pinholes, as an efficient power and energy limiter in flashlamp (pulsed) and arc lamp (CW) pumped actively passively mode-locked crystalline Nd-doped lasers. Power limiting by the intracavity two-photon absorber is exploited to create the condition for optimum pulse compression in the saturable absorber. Additional pulse shortening is due to the elimination of the pulse tail by self-defocusing in the nonlinear crystal. Extracavity and intracavity measurements, as well as three-dimensional computer simulations, give a complete understanding of the pulse evolution in the cavity, including the two mechanisms of pulse shaping and compression.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>