Extention of Tuning Range of Ti: sapphire Lasers Pumped by a Pulsed Laser

Cavity conditions of Ti: sapphire lasers pumped by a pulsed laser were investigated from a standpoint of the extention of the tuning range. Analytical calculation predicts that the tuning range increases with increasing pump light fluence into the Ti: sapphire crystal, and with de-creasing cavity loss. Therefore, the extention of the tuning range is obtained by increasing the reflectivity of output mirror and by using a low-loss prism tuner instead of a glazing incidence grating. Increasing the pump light fluence is effective, but that is limited by the damage threshold of the crystal. Practically, the wavelength dependance of the cavity mirrors also nar-rows the tuning range. Experimentally, a tunable operation over 700nm to 925 nm is achieved with a prism tuner and a pair of broad-band mirrors at a moderate pump light fluence less than 2J/cm2.