Efficient red-edge materials photosensitized by Rhodamine 640.

We report on tunable, highly efficient and photostable solid-state dye laser emitting around 640 nm based on Rhodamine 640 incorporated into homopolymers, linear and cross-linked copolymers, and silicon-modified organic matrices. The effect on the lasing properties of both dye concentration and environmental conditions was analyzed. Under transversal pumping at 532 nm with 5.5 mJ/pulse, high-lasing efficiencies of up to 42% were recorded. The laser operation was highly stable with a drop in the laser output of approximately 20% after 100 000 pump pulses at the same position of the sample at 10 Hz repetition rate. To the best of our knowledge, these results are the topmost achieved to date for organic, inorganic, and hybrid materials doped with rhodamine 640. When the samples were incorporated into a grazing-incidence grating oscillator, narrow-line-width operation with tunning ranges of up to 40 nm was obtained.