Development of a composite polymer-dye medium for tunable laser emission

Abstract

We demonstrate optically pumped laser medium with emission in the visible spectral range from binary solutions of Rhodamine 6G and Rhodamine B in epoxy resin as matrix without appending additional scattering centers. A frequency doubled Q-switched Nd: YAG laser was used for pumping. The generation’s behavior is similar to random laser (RL) with no external optical resonator. The influence of the nanostructured morphology of the medium on the laser properties was investigated by means of SEM, AFM, TEM, SAED, Spectrofluorimetry and Spectrometry. The laser emission is characterized by high intensity – energy per pulse – 300 µJ, threshold pump energy 1.7 mJ, relatively low beam divergence of 70 mrad (for RL) and spectrally narrowed major peak at 597 nm. The new gain medium was also investigated in a conventional tunable resonator. Generation with continuous tuning in the spectral range 590–610 nm was obtained. This new effective nanostructured medium, which shows with high optical and energy parameters, can be used in speckle-free laser imaging, time-resolved microscopy, high speed optical converters and others photonics applications.