Highly controllable optical bistability effect in a 2 μm Tm:YAG ceramic laser at room temperature.

A highly controllable optical bistability in a Tm:YAG ceramic laser system is reported, which is attributed to the thermal-induced change in the stability of the resonator. The width of the bistable region can be tuned in a large scale from 0.8 W to 6.3 W. At nearly semi-confocal cavity configuration, a second lasing condition was observed in the bistable region with a modulated shape of the laser beam and a broadened laser spectrum. The influence of the temperature on the bistable laser operation was also discussed in detail. To our knowledge, this is the first report on the optical bistability effect in Tm:YAG ceramic lasers.