Tian Yu-peng

Synthesis and Nonlinear Optical Characterization of a New Organic Dye DMAHAS

The title compound DMAHAS has been synthesized and characterized by 1 H-NMR spectra, IR spectra, and elemental analyses. Linear absorption, single-photon induced fluorescence and two-photon induced fluorescence are experimentally studied. This new dye has a moderate two-photon absorption cross-section of σ 2 = 0.91 2 10 m 46 cm 4 - s/photon at 532 nm by using an open aperture Z -scan technique. When pumped with 800 nm laser irradiation, DMAHAS shows a strong two-photon induced blue fluorescence of 432 nm.

Four-Photon Process Induced Upconversion Lasing

It is measured that upconversion fluorescent intensity of a new molecule is proportional to the quartic of excitation density. This demonstrates that it is a four-photon absorption process. Furthermore, at high-density ultrashort pulse laser pumping, an emission appears to satisfy four criteria of lasing, including the highly directional emission, the short emission duration, the spectral narrowing, and changing to linear output/input relationship above a threshold. The experimental results demonstrate that the four-photon-process-induced amplified spontaneous emission occurs.