Diode-pumped solid state laser with 2D intracavity beam scanning using liquid crystal spatial light modulator

Abstract

The problem of swift steering of laser beams is important for many applications, (projection, marking, engraving, etc.). An approach of intracavity laser beams spatial control was proposed and developed by several teams [1 -9, 14] . Laser beam movement is provided, with thisapproach, by the positioning of the ruling diaphragm across the surface of one of mirrors of conjugate laser cavity. The ruling diaphragm can be done as a Spatial Light Modulator (SLM). Such modulators are based on various physical effects and can use various modulating media: electrooptical crystals [2, 10], thin semiconductor layers [1 1], ferro-electrical ceramics [12-14], or liquid crystals [6,8]. The electrically-addressed intracavity Spatial Light Modulators (SLMs) were experimentally shown to provide computer-controlled beam addressing to any pixel insidelaserFieldOfView (FOV) [12, 13,14] In the presented article the following aspects are treated of such laser development: (a) design and properties of iniracavity LC SLMs with random addressing to arbitrary pixel in 2D field, and (b) some peculiarities ofDPSSL with intracavity beam scanning, in terms of SLM operation inside the cavity, and thermal lens influence on the laser FOV