DISTRIBUTED-FEEDBACK SOLID-STATE POLYMERIC-DYE LASERS BASED ON EXCITATION-ENERGY TRANSFER

摘要

Using Q-switched Nd:YAG laser excitation, we investigate both theoretically and experimentally the energy transfer between dyes Pyronin-Y (PY) and cresyl violet (CV) incorporated in a methyl methacrylate (MMA) matrix. From the absorption and fluorescence spectral data of PY and CV dyes, we calculate the absorption and emission cross-section of donor and acceptor dye molecules, the critical transfer radius Ro, the critical concentration Co, the half-quenching concentration C_(1/2), and the Foster-type transfer rate k_f. We study the influence of donor-acceptor concentration and pump power on the energy transfer and its mechanism. Both energy transfer phenomenon and the self-absorption mechanism play a role in laser tunability. We achieve a tuning of the output wavelength (between 580 and 670 nm) by varying the periodic gain modulation generated by a Q-switched Nd:YAG laser.