DISPERSIVE SOLID-STATE DYE-LASER OSCILLATORS

Narrow-linewidth multiple-prism grating solid-state dye laser oscillat ors are analysed using ray transfer matrices. Attention is given to be am divergence measurements and the effect on them of thermal lensing, at the solid-state gain medium. It is found that although thermal lens ing leads to an increment of beam divergence, it induces oscillation i n the unstable resonator regime, thus contributing to the attainment o f TEM00 beam profiles. In addition, narrow-linewidth emission in dispe rsive oscillators, incorporating rhodamine 6 G doped HEMA:MMA gain med ia, is reported for the first time. Laser efficiency is 4-5% at a lase r linewidth less than or equal to 1.8 GHz for double-longitudinal-mode emission. Beam divergence is measured in the 2-2.3 mrad range, in goo d agreement with theory.