Kilohertz gain-switched laser operation and femtosecond regenerative amplification in Cr:forsterite

We present a comprehensive study of the optimum operating regime in a gain-switched Cr:forsterite laser at a repetition frequency of 1 kHz with special attention to temperature-dependent and parasitic absorption effects and proper resonator design. On the basis of the results achieved, me demonstrate highly efficient (13% extraction efficiency) operation of a femtosecond regenerative amplifier based on Cr:forsterite and operating near room temperature with a novel BBO Pockels cell that is highly resistant to optical damage. Chirped pulse amplification raises the pulse energy to 355 /spl mu/J in /spl ap/30 cavity round trips which corresponds to an amplification factor of /spl ap/5.5/spl times/10/sup 5/. The nearly transform limited 200-/spl mu/J 135-fs compressed pulses near 1.25 /spl mu/m have a peak power of /spl ap/1.5 GW. Frequency doubling with 52% conversion efficiency in LBO produces femtosecond pulses of 104-/spl mu/J energy in the visible near 625 nm.