I. N. Lapin

Emission of Concentrated Solutions of Organic Compounds Excited with High-Power Laser Radiation

Specific features of emission of concentrated (C ≤ 1.2·1019 cm–3) solutions of organic molecules (rhodamine 6G, rhodamine C, phenalemine 512, and substituted paraterphenyl (LOC-1)) are investigated as functions of the exciting photon energy (at λexc = 308 and 532 nm) and power density of exciting radiation (up to 1 GW/cm2). One of the observed emission types – band emission – is studied. The intensity of band emission (its short- and long-wavelength maxima) is investigated versus the exciting radiation power density, and its time and polarization characteristics are also analyzed. The results obtained together with the specific features of the emission spectrum of concentrated rhodamine-C solution, measured after passage of sounding radiation with maximum at the wavelength equal to that of the short-wavelength maximum of band emission, demonstrate that the band emission is simply superfluorescence.

Specific Features of XeCl*-Laser Radiation Absorption by Concentrated Solutions of Organic Dyes

The transmission of focused laser radiation with power densities in the range (1–250) MW/cm2 through solutions of laser dyes (substituted paraterphenyls and rhodamine 6G) is investigated. The dependence of the transmission on the exciting radiation power density is measured, and numerical modeling is used to estimate the lifetime of the fluorescent state of molecules and the influence of stimulated emission on the lifetime of the S1 state. The effect of scattering on the transmission of highly absorbing media is demonstrated under nanosecond excitation.