Department of Physics2024-11-1020110146-959210.1364/OL.36.0015722-s2.0-79956324834http://dx.doi.org/10.1364/OL.36.001572https://hdl.handle.net/20.500.14288/16380We report direct generation of 81 nJ chirped pulses from a room-temperature, Kerr lens mode-locked Cr4+:forsterite oscillator operating at 1258nm. To increase the pulse energy, the pulse repetition rate of the short x-type resonator was lowered from 143 to 4.9 MHz by the addition of a q-preserving multipass cavity, which provided an additional effective optical path length of 59.4m. The duration of the chirped pulses was around 5.5 ps with a spectral width of 21nm. The pulses were externally compressed to 607 fs by using a diffraction grating pair. To our knowledge, this is the highest reported pulse energy directly generated from a room-temperature mode-locked Cr4+:forsterite laser. (C) 2011 Optical Society of AmericaOpticsJournal Article2900373000161406