Longitudinally Two-Photon Pumped Leaky Waveguide Dye Film Laser

Longitudinally two-photon pumped (TPP) and frequency-upconverted cavity lasing is achieved in a planar leaky waveguide configuration which utilizes a dye-doped polymer film coating on the surface of an optical glass prism. The TPP lasing dye is 4-dimethylamino-N-methylstilbazolium tosylate (DAST) that has been extensively studied as a second order nonlinear optical material. The spectral, temporal, and spatial structures as well as the output-input characteristics of the TPP cavity lasing were measured using a ~170-μm-thick film with a ~2.4-mm pump depth. The leaky waveguide lasing was featured by a nearly single transverse-mode and five axial-modes structure. In our preliminary study, the net conversion efficiency from the absorbed 1064-nm pump pulse energy to the output ~607-nm upconverted cavity lasing energy was found to be ~0.65%. However, this efficiency can be considerably increased by further optimizing the system parameters.