Mode-locked Nd:YAG laser using Cr/sup 4+/:YAG crystal at 1.064 /spl mu/m

Summary form only given. Cr/sup 4+/:YAG has been used for saturable absorption Q-switching to achieve a giant pulse in the Nd:YAG laser. For the long lifetime of the excited-state (3.2 /spl mu/s), it is difficult to create the mode-locking effect as a general saturable absorber. However recently, with the discovery of the excited-state-absorption (ESA) of Cr/sup 4+/:YAG, it becomes possible to mode-lock the Nd:YAG laser at 1.064 /spl mu/m by the short lifetime of the upper-excited-state (50 ps). In the paper, we have achieved the complete and stable pulse train in an active-passive mode-locked Nd:YAG laser using Cr4+:YAG as a saturable absorber. The widths (FWHM) of the pulse envelopment and every single pulse were 120 ns and 2 ns (shorter than the early report) respectively.