SPECTROSCOPY AND LASER CHARACTERISTICS OF COPPER-VAPOR-LASER PUMPED PYRROMETHENE-556 AND PYRROMETHENE-567 DYE SOLUTIONS

We measured the basic optical properties of Pyrromethene-567 (P567) an d Pyrromethene-556 (P556) dye solutions that are relevant to their app lication as dye lasers. The fluorescence spectra of methanol solutions show mirror images in relation to the absorption spectra, with Stokes shifts of 29.5 and 37.5 nm, respectively, for the two dyes. The centr al fluorescence peaks were at 546 and 535 nm, with widths of similar t o 40 and similar to 50 nm (FWHM). The quantum yields were 97% +/- 5% a nd 78% +/- 5% for P567 and P556, respectively. Fluorescence lifetimes of 6.0 +/- 0.2 ns were obtained for both dyes in methanol. Laser actio n, obtained by pumping with the green emission line (510.6 nm) from a copper-vapor laser, was measured in a Hansch-type cavity. Tunability r anged from 531 to 590 ma for P567 and from 522 to 590 nm for P556. Las ing thresholds were similar to 0.27 and similar to 0.16 mJ/pulse, with 25% and 27% slope efficiencies for P567 and P556, respectively Spectr oscopy and lasing were studied in other solvents as well. (C) 1998 Opt ical Society of America.