Influence of the pump wavelength on the parameters of lasing of complex organic compounds in the gaseous phase

Lasing was observed in pentane-stabilized vapors of 1,4-di[2-(5-phenyloxazolyl)]benzene (POPOP) and 1,4-di(benzoxazol-2'-yl)benzene (BOPBO) pumped by KrF* excimer laser radiation (λ_p = 248 nm). An investigation was made of the dependences of the threshold pump power density W_p.th on the pentane pressure, on temperature, and on the vapor pressure of the lasing substance at pump wavelengths λ_p = 248, 308, 337, and 350 nm. In the case of BOPBO the minimum threshold power density was W_p.th = 250 kW/cm².