New laser medium: Dye-doped sol-gel fiber

Rhodamine-6G, a well-known laser dye, was doped in a sol-gel-derived fiber. For the first time, lasing was demonstrated from a dye-doped sol-gel-derived fiber device. Lasing was demonstrated under excitation with an 8 ns pulsed, frequency-doubled Nd: YAG laser at 532 nm operating at a 1/2 Hz repetition rate. The dye-doped fiber was pumped longitudinally and placed in a cavity consisting of a ∼ 100% reflecting flat mirror and a ∼ 70% reflecting flat output coupler. The lasing emission peak for a 2 × 10^-5 M Rhodamine-6G doped fiber was observed at ∼ 568 nm with a full width at half maximum of ∼ 7 nm. A slope efficiency of ∼ 2.8% was observed for a 1 × 10^-4 M Rhodamine-6G doped fiber. A much higher slope efficiency is expected by improving the coupling into the fiber, decreasing the intrinsic fiber optical losses, optimizing the concentration-length relationship (preventing aggregation effect) and improving the cavity design.