Abstract

Direct generation of optical pulses with duration below 100 fs from cw dye lasers has almost exclusively been limited to the 605–630-nm spectral range. Typically, the use of conventional ring or antiresonant ring cavity arrangements designed to utilize the colliding pulse mode-locking (CPM) effect,¹ where counterpropagating pulses meet in a saturable absorber jet stream, is also required. We describe the generation of near transformlimited pulses as short as 55 fs at 675 nm and 69 fs at 583 nm from a linear cavity, synchronously pumped, hybrid cw dye laser which does not require the CPM technique. The laser was pumped at 82 MHz by 650-mW average power, 70-ps pulses from a mode-locked and frequency-doubled cw Nd:YAG laser. The dual-jet resonator was terminated by a two Brewster prism and plane mirror arrangement used to introduce variable intracavity dispersion. Optimal laser performance was achieved by iterative adjustments of the intracavity dispersion and cavity length. Femtosecond pulse generation was obtained using the gain/absorber dye combinations of sulphorhodamine 101/DQTCI and rhodamine 6G/DQOCI and DODCI mix. Average output powers were 35 mW at 675 nm and 55 mW at 583 nm, respectively, for these combinations.

© 1986 Optical Society of America