| abstract |
Laser light in the wavelength range of 400 - 480 Nm is obtained with a dyestuff laser containing a dyestuff of the general formula ##STR1## wherein E denotes one of the radicals ##STR2## R 1 -R 4 independently of one another denote hydrogen, alkyl, trifluoromethyl, alkoxy, aralkoxy, halogen, alkenyloxy, the carboxyl, cyano, alkylsulphone, arylsulphone, carboxamide or sulphonamide group or the carboxylic acid ester group, or R 1 and R 2 , or R 3 and R 4 , conjointly represent a fused benzene ring and m and n independently of one another denote 0, 1 or 2, with the proviso that the radical E contains at least one sulphonic acid group if m and n represent 0, n and wherein n the radical E can be further substituted, in a solvent which does not interfere with the emission, at a concentration, which emits laser beams, of, preferably, 10 -2 to 10 -5 mols/liter. |