SPECTRAL PROPERTIES OF A TM-HO-YAG LASER IN ACTIVE MIRROR CONFIGURATION

A Tm3+:Ho3+:YAG laser is operated in active mirror configuration. This laser is characterised by a rather thin crystal (3 mm thickness in ou r experiment) and a very short resonator (about 3.2 mm). Therefore thi s laser is well suited for operation in a single longitudinal mode. Si ngle-frequency operation is demonstrated with and without an intracavi ty etalon, It is further shown that single-frequency emission is reach ed with a stable cw emission. With a slight detuning of the outcouplin g mirror, spiking can be achieved, resulting in an emission on differe nt lines. The assignment of the observed laser lines to the known tran sitions between Stark sublevels of the I-5(7) and the I-5(8) level is discussed and compared with predictions in the literature.