Tunable organic thin-film laser pumped by an inorganic violet diode laser

We demonstrate an organic thin-film distributed feedback (DFB) laser pumped by an inorganic violet laser diode (lambda=406 nm). The active organic medium consists of a highly efficient, modified poly(9,9-dioctylfluorene) derivative containing 12% of statistical intrachain 6,6(')-(2,2(')-octyloxy-1,1(')-binaphthalene) binaphthyl spacer groups. The polymer is doped with 4 wt % of the stilbene dye 1,4-bis(2-(4-(N,N-di(p-tolyl)amino)phenyl)vinylbenzene). This guest-host system features minimum lasing threshold energy densities below 1 mu J/cm(2) for second order DFB resonator geometries and significant absorption (7.3x10(4) cm(-1)) at the wavelength of the pumping diode laser. The entire setup states an extremely compact and cost effective, laser source tunable between 496 and 516 nm.