WAVE-GUIDED VISIBLE LASING EFFECTS IN A DYE-DOPED SOL-GEL GLASS-FILM

We report the first laser action in waveguiding films of dye-doped sol -gel glass. Rhodamine B (RB)-doped films were prepared that were pumpe d by frequency-doubled Nd:YAG laser light focused by means of a cylind rical lens. Fresnel back-reflections of the order of a few percent at the edge of the film provided sufficient feedback to change significan tly the characteristics of the emitted light. Output energies were enh anced by factors up to five and pumping threshold energies significant ly reduced, down to pumping energies of 15 mu J/pulse. Laser action wa s also evidenced by a pulse narrowing effect. Gain measurements on add itional dye dopants, Rhodamine 6G, perylimide dye LFR and sulfoRhodami ne 640, that yielded gain coefficients in the range of 120-200 dB/cm a re also reported here.