Coumarin 6 as the active medium of a dye vapor laser with wide-band optical pumping and specific characteristics of such lasers

An experimental investigation was made of the efficiency of conversion of flashlamp pump radiation to fluorescence of coumarin 6 at a buffer gas pressure of 0–1 MPa. The lasing dynamics of the flashlamppumped vapor of this compound was also studied. It was found that the fluorescence quantum efficiency averaged over the absorption spectrum, which characterized the pump conversion efficiency, was < η > ≤ 0.3 at a buffer gas pressure of 0–1 MPa. Dependences of <η> and the rate constant for optical bleaching of the dye on the buffer gas pressure were determined. A comparative analysis of the lasing dynamics of coumarin 6 in vapors and in an ether solution showed that the gas phase had a higher lasing threshold (18–20 times higher) and a larger increment of loss growth in the spectral range of lasing (four times higher). It also had a shorter maximum lasing duration (t_max ≈ 500 nsec).