Self-stabilized single-longitudinal-mode operation in a self-Q-switched Cr,Nd:YAG laser.

Single-longitudinal-mode operation in a homogeneously broadened solid-state laser is often impeded by spatial hole burning. To maintain a single longitudinal mode, it is necessary to eliminate spatial hole burning, for example, by introducing quarter-wave plates at both ends of the gain medium' or by using a ring cavity.2 In a standingwave resonator, an additional wavelength-selective element, such as an 6talon3'4 or a mirror,5 can also lead to single-longitudinal-mode operation. Active techniques such as seeding6'7 and the prelase methods have also been reported. The use of a microchip cavity is also effective. 9