Zhao Xian

Effect of S Substitution for P Point Defects in KDP Crystals: First-Principles Study

The electronic structure and geometric distribution of phosphor replaced by sulfur in potassium dihydrogen phosphate (KDP) are investigated by first-principles calculations. The point defect narrows down the energy gap to about 4.9 eV, corresponding to a two-photon absorption of 355 nm after correction. This can explain the decrease of the laser damage resistance in KDP crystals. Moreover, the defects twist the crystal structure and weaken bonds, especially the O-H bonds, so these bonds may be the first sites to crack under laser irradiation.

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.

Synthesis and Properties of a New Two-photon-absorbed Material Heasps

Abstract A new dye Trans-4-[p-(N-hydroxyethyl-N-ethyiamino)styryl]-N-methylpyridinium p-toluene sulfonate (HEASPS) was synthesized, and the two-photon absorption (TPA), TPA-induced frequency up-conversion emission, and two-photon pumped (TPP) frequency up-converted lasing properties of this new dye were experimentally studied. This new dye has a moderate TPA cross-section of\sigma2 = 4.7 × 10−48 cm4 .s/photon at 1064nm, but exhibits a high lasing efficiency. The net conversion efficiency from the absorbed 1064 nm pump pulse energy to the 626 nm up-converted lasing energy is 18.2% at the pump energy level of 1.9 mJ.