Laser properties of pyrromethene dyes in sol-gel glasses

Solid-state dye lasers were made by incorporating pyrromethene dyes in organically modified silicate (ormosil) and composite glass matrices. Three different types of pyrromethene (PM) were used: PM 567, PM 580 and PM 597. The ormosil glass samples were prepared by a one-step process at room temperature sol-gel technology which led to the formation of hybrid organic/inorganic materials. The composite glass samples are made by a biphase process: (a) preparation of porous silica gel, (b) impregnation of the dye dissolved in methylmethacrylate (MMA) into the silica gel. A number of various glass compositions were tested and their efficiencies and half output energy lifetimes were measured. The optimal slope efficiency for the lasers pumped transversally, by frequency doubled Nd-Yag laser, approaches 42%. Fluorescence lifetimes, excitation and emission spectra were also measured. In addition, significant dependency of these dyes on pH was found. These dyes lose their lasing ability in acidic (pH < 3) surroundings. This must be considered in the sample preparation.