Two-element-cavity femtosecond Cr4+: YAG laser operating at a 2.6-GHz repetition rate

A femtosecond Cr4+:YAG laser with a simple two-element cavity was built. Th is laser typically attained a repetition rate of 2.64 GHz with a pulse widt h of 115 fs at a center wavelength of 1540 mn. Output pulses were character ized by second-harmonic generation frequency-resolved optical gating. Align ment of the two-element cavity for mode-locked operation was easy; moreover , the cavity structure has the potential to produce an even higher repetiti on rate because one can miniaturize it simply by shortening a gain medium l ength. (C) 2001 Optical Society of America.