Femtosecond Beam Generation

Abstract

The first issue in the field of terawatt (TW) lasers is the oscillator principle for generating ultrashort pulses.Conventional pulsed lasers are based on the Q-switching principle. The laser cavity is made of a gain medium and a switching element that triggers pulse emission. The Q switch, which can be either acousto-optical or electro-optical (the Pockels cell principle), is a variable loss element (oscillator Q modulator) and usually exhibits a switching time in the nanosecond range. Such devices do not generate pulses below the nanosecond range.