Near-IR lasing in caesium vapour

Lasing in caesium vapour is obtained at lambda similar to 3 mu m (transitions 7P(3/2) -> 7S(1/2) and 7P(1/2) -> 7S(1/2)). Longitudinal pumping is performed by the second harmonic of a parametric oscillator pumped by the second harmonic of a Nd3+-doped garnet laser. The pump wavelength corresponds to the 6S(1/2) -> 7P(3/2) and 6S(1/2) -> 7P(1/2) transitions of caesium atoms. The pump radiation has a spectral width of 12 cm(-1), a pulse energy of 10 mJ, and a pulse repetition rate of 10 Hz. The IR laser pulse energy at a vapour cell temperature of 155 degrees C is 100 mu J. The efficiency of pump energy conversion to the laser radiation energy at lambda similar to 3 mu m is similar to 1.5 %.