New photostable UV laser dyes

There is considerable interest in the development of photostable and tunable laser dyes emitting in the 300–400-nm wavelength range for use in analytical chemistry, spectroscopy, and various other fields of application. From a large class of substituted and ring-bridged p-quaterphenyls and 2,6-diphenyl-benzo[1.2d;4.5d'] bisoxazoles potential laser dyes have been preselected by an empirical approach consisting of correlating their photophysical characteristics (high fluorescence quantum yield, short fluorescence decay time) with the cross sections for stimulated emissions. The following laser dye properties of substituted and ring-bridged p-quaterphenyls as well as substituted 2,6-diphenyl-benzo [1.2d;4.5d'] bisoxazoles have been measured with an excimer laser and dye laser operating on XeCI excimer emission of 308 nm: tuning range, lasing threshold, conversion efficiency (slope efficiency), and photochemical stability under pump laser excitation.