Single-mode operation of a standing wave miniature Nd laser pumped by laser diodes

Single-longitudinal-mode operation is reported for miniature Nd:YAG and Nd:BEL standing wave resonators. The best performance obtained was 18 mW with laser diode pumping and 31 mW with dye laser pumping. The miniature lasers were also operated multimode at power levels as high as 470 mW. A completely integrated, miniature Nd:BEL laser was constructed and is described. Results for several different resonator configurations are compared and it is concluded that the threshold pump power for multimode oscillation in each is consistent with an earlier observation that energy diffusion increases with absorbed pump power density. This allows single frequency oscillation to be obtained at high excitation rates with axially extended cavities.