Neutralisation of parasitic photorefraction in a laser with electrooptic negative feedback

Abstract

The boundaries of the stable operation region were determined experimentally for an yttrium laser with active negative feedback and a photorefractive electrooptic control component in the resonator. The relationship was established between the boundaries of the stability region and photorefractive parameters of the electrooptic cell, feedback coefficient, integration constant of the signal in the feedback loop, and the laser radiation power. When the integration constant exceeded 2×10-8 s, tuning to single-pulse lasing was of resonant nature, i.e. the single-pulse output power was a function of the negative feedback coefficient, confirming the results of analytic predictions. The conditions were found under which single-pulse lasing occurred in a wide range of pump intensities (the maximum experimentally determined energy density of laser radiation inside the resonator was 30 J cm-2). The effectiveness of electronic tuning of the duration of single pulses was demonstrated. The experiments were carried out on a commercial Kvant-15 laser and the result could be used in the modernisation of technological laser equipment.