Internal photostabilization of polymeric solid-state dye lasers based on trichromophoric rhodamine 6G molecules

We report on the lasing action of a modified rhodamine 6G dye with two covalently bonded identical 1,8-naphthalimide groups in liquid solution in ethanol and in solid solutions in a methacrylate copolymer. When the solid samples are transversely pumped with 534 nm pulses at a repetition rate of 1 Hz, we have observed that the presence of the naphthalamide groups results in a clear photostabilization of the material. Possible mechanisms for the photostabilization process are suggested.