Abstract

We report on the first successful generation, to our knowledge, of femtosecond pulses from an actively mode-locked chromium-doped forsterite laser with intracavity dispersion compensation. Mode-locked operation of the forsterite laser was achieved when an acousto-optic modulator was inserted in a basic Z-fold cavity, without prisms. A stable train of 6-ps FWHM pulses was obtained. The FWHM of the bandwidth was measured to be 1.2 nm. The pulse duration–bandwidth product Δτ_pΔν = 1.34 indicated that the pulses were strongly chirped. To compensate for the chirp, a pair of high-dispersion Brewster prisms was inserted in the cavity. This resulted in significant reduction in pulse duration, down to 90 fs, with spectral bandwidth of the order of 19 nm, giving transform limited pulses (ΔτΔν = 0.32). Pulses as short as 60 fs FWHM were measured. The pulses were tunable over 1220–1290 nm.

© 1992 Optical Society of America