<title>Lasing characteristics of phenolemine 512 and pyrromethene 580 dyes, impregnated to polymer-filled nanoporous glass, at various excitation wavelengths</title>

Abstract

A polymer-filled nanoporous glass composite (PFNPG) has been shown recently to be a very attractive host material for solid-state dye lasers. In particular, a high-conversion (lasing) efficiency, up to 70%, has been demonstrated for pyrromethene-family dyes impregnated to PFNPG, in a visible spectral range at 2-nd harmonic nanosecond pulse duration Nd:YAG laser excitation. For development of PFNPG-based dye lasers it is important to investigate lasing characteristics of this type matrices at various excitation (pump) wavelengths. In this context we have investigated the conversion efficiency, η, and emission spectra, f_em, of phenolemine 512 (Ph 512) and pyromethene 580 (PM 580) dyes impregnated into PFNPG, at excitation wavelengths, λ_p, varied in a range of their main absorption bands. A microsecond pulse duration liquid solution dye laser was used in our experiments as a pump source. The conversion efficiency, η=32% and 47%, has been observed at λ=525 nm for Ph 512 and PM 580 respectively with output energy as high as 250 mJ. "Anomalous" dependencies of η and f_em upon λ_p have been revealed for both dyes. In particular, two-frequency lasing has been observed for Ph 5 12 at λ=535 nm. Mechanism of the lasing anomalies is supposed to be related to photoinduced absorption in lasing dyes.