Pyrromethene-BF 2 laser dyes

Abstract

The pyrromethene-BF<SUB>2</SUB> (P-BF<SUB>2</SUB>) complexes are a new class of efficient laser dyes that exhibit laser action from the green to the red spectral region. Some of these dyes outperform commercially available dyes, showing laser action in the same spectral region. We, therefore, are presenting experimental data on laser action efficiency under flashlamp, cw laser, and synchronously pumping of some typical P-BF<SUB>2</SUB> laser dyes. The main reason for the improved performance of the new laser dyes is reduced triplet state absorption over the fluorescence spectral region of the triplet state P-BF<SUB>2</SUB> molecules. Triplet state losses in laser dyes are briefly reviewed. Some general criteria for obtaining improved laser dyes are discussed. Because of the long triplet state lifetime (tau) <SUB>T</SUB> of the P-BF<SUB>2</SUB> molecules in solution, these dyes do not yet exhibit maximum laser action efficiencies under flashlamp excitation.