Bandwidth-limited picosecond pulses from a YSGG:Cr3+:Er3+ laser (λ=2.79 µ) with active mode locking

Ultrashort λ=2.79 µ pulses were generated in an yttrium scandium gallium garnet crystal laser activated with chromium and erbium. Active mode locking and synchronous electrooptic modulation of the resonator losses were used. The duration of bandwidth-limited (τΔν≈0.5) single laser pulses selected from a train could be varied in discrete steps by intracavity spectral selectors within the range 40–220 psec (repetition frequency 1 Hz). Continuous tuning of the emission spectrum of the laser was possible within a range of 1 cm^–1 near the center of the gain profile. When the energy of a single spike was 4 mJ ( in a four-pass amplifier) and the pulse duration was τ = 40 psec, the power of the laser radiation in the form of the TEM₀₀ mode was 100 MW.