Optically (solar) pumped oxygen-iodine lasers

We present the results of theoretical and experimental studies demonstrating the possibility of developing an oxygen-iodine laser (OIL) with direct optical pumping of molecular oxygen involving inter-molecular interaction with charge transfer from donor molecule (buffer gas) to acceptor molecule (oxygen). This interaction lifts degeneracy of the lower energy states of molecular oxygen and increases its absorption cross section in the visible spectral region and the UV Herzberg band, where high quantum yield of singlet oxygen is achieved (QY ∼ 1 and QY ∼ 2, respectively) at the same time. A pulse-periodic optical pump sources with pulse energy of ∼50 kJ, pulse duration of ∼25 μs, and repetition rate of ∼10 Hz, which are synchronized with the mechanism of singlet oxygen generation, are developed. This allows implementation of a pulse-periodic oxygen-iodine laser with an efficiency of ∼25%, optical efficiency of ∼40%, and parameter L/T ∼ 1/1.5, where T is the thermal energy released in the laser active medium upon generation of energy L. It is demonstrated that, under direct solar pumping of molecular oxygen, the efficiency parameter of the OIL can reach L/T ∼ 1/0.8 in a wide range of scaling factors.