A multi-kilohertz electro-optic switch for ultrafast laser systems

Summary form only given.We report on the use of a multi-kilohertz intracavity electro-optic switch to both efficiently cavity-dump a femtosecond Ti:sapphire oscillator and perform the switching for a high-repetition-rate Ti:sapphire regenerative amplifier. The polarization switch consists of a transverse-field KD*P Pockels cell and a novel near-Brewster sapphire Rochon polarizer. In contrast to more conventional longitudinal Pockels cells with dielectric thin-film polarizers, this switch is capable of 50 kHz operation and near 100% switching efficiency due to the Rochon polarizer's high extinction ratio (>10/sup 4/:1) and low insertion loss (nominally 100% transmission for the undeviated p-polarization and <2% loss for the rejected s-polarization). Moreover, its low dispersion (/spl sim/60 fs/sup 2/ for the 10 mm of sapphire), broad operational bandwidth (>100 nm about the central design wavelength), and high damage threshold (>10 GW/cm/sup 2/) are attractive properties for ultrafast laser systems, especially regenerative amplifiers.