Laser beam cleanup by mode filtering and photorefractive two-wave mixing

Abstract

In a recent paper1 the authors reported the cleanup of spatial and temporal phase aberration using photorefractive two-wave mixing in a strontium barium niobate crystal. The unique property that energy transfer takes place in photorefractive beam coupling without phase crosstalk is clearly demonstrated. The authors also used a phase distorter to simulate a poor quality crystal and demonstrated2 that such distortion can be corrected using a scheme combining the merits of phase conjugation and two-wave mixing. In this presentation, we describe how similar schemes can be used to transfer energy from the spatial sidelobes of a laser beam to the central lobe.