Low mode-locking saturation intensity of co-doped Nd3+,Cr4+:YAG crystal as saturable absorber

We report the characteristics of low saturation intensity of Nd,Cr:YAG as saturable absorber both in a diode pumped Nd:YAG laser and a self-mode-locking Nd,Cr:YAG laser. The difference of saturation intensity between Q-switched and mode-locked operation in co-doped Nd,Cr:YAG was only one to two orders of magnitude while the reported difference in Cr:YAG was five orders of magnitude. More than 80% passive mode-locking modulation depth was achieved at an intracavity intensity of 6 x 10(4) W/cm(2). Self-mode-locking phenomenon was observed in a fiber-coupled laser diode pumped Nd,Cr:YAG laser at an intracavity intensity of 1.0 MW/cm(2). The modulation depth is approximately 40%. (C) 2002 Published by Elsevier Science B.V.