Abstract

Using dual-crystal, thermally compensated, LiNbO₃, and KTiOPO₄, (KTP) electro-optic modulators, we have demonstrated 250 and 65 watts, respectively, of Q-switched average power at thermal loadings approaching 1 kW/cm².¹⁻² The low surface damage threshold of LiNbO₃, and the limited aperture of KTP poses a problem for devices operating at moderate fluences (3-5 J/cm²) or requiring apertures greater than 2 cm². For these applications, KD₂PO₄ (DKDP) remains as the Using dual-crystal, thermally compensated, LiNbO₃, and KTiOPO₄, (KTP) electro-optic modulators, we have demonstrated 250 and 65 watts, respectively, of Q-switched average power at thermal loadings approaching 1 kW/cm².¹⁻² The low surface damage threshold of LiNbO₃, and the limited aperture of KTP poses a problem for devices operating at moderate fluences (3-5 J/cm²) or requiring apertures greater than 2 cm². For these applications, KD₂PO₄ (DKDP) remains as the only electro-optic crystal available in large apertures with high optical homogeneity and with damage thresholds exceeding 10 J/cm. However, the relatively low thermal conductivity, high near-infrared optical absorption, and low fracture strength makes DKDP difficult to use for high average power applications.³ The Mercury laser project at Lawrence Livermore National Laboratory is a 100), 10 Hz (1 kW) prototype of a potential inertia] fusion energy driver.¹¹ A moderate aperture (3×5 cm²) electro-optic cell which can handle 100 W of average power is required for use as an isolation device. We have built and tested a scaleable, half-aperture, dual DKDP crystal Pockels cell, which, in off-line testing, exhibits less than 0.5% depolarization when thermally loaded with a 100 W near-infrared laser.

© 2002 Optical Society of America