Abstract

We have experimentally observed an intense electro-optic alteration of the transversal beam-shape of a gausian beam passing through a PPLN crystal where the domain patterned region is sandwiched between two mono-domain (unpoled) regions (Fig. la). The effect is strong enough to lead to low voltage driven electro-optic Q-Switch when the PPLN crystal is placed intra-cavity to a 1064 nm Nd³⁺:YVO₄ laser. By heating the crystal to a suitable QPM temperature, Q-Switching and efficient intra-cavity frequency doubling to 532 nm may be realized simultaneously. As compared with previous schemes based on polarization rotation with intra-cavity PPLN crystals [1,2], this novel Q-Switching technique requires no additional intra-cavity optical elements such as Brewster plates. It may be implemented in simple composite miniature lasers based on bonding a laser crystal to a PPLN crystal and depositing dielectric mirrors on both laser ends, as all that is required is deposition of electrodes in the crystal and application of an external voltage.

© 2009 IEEE