Zhang Xipeng, Jiang Hongbing, Chen Li, Jiang Yingying, Yang Hong, Gong Qihuang
Department of Physics and State Key Laboratory for Mesoscopic Physics, Peking University, Beijing, China.
Opt Lett. 2008 Jun 15;33(12):1374-6. doi: 10.1364/ol.33.001374.
A femtosecond light pulse at 480 nm in wavelength was generated during filamentation of an intense 808 nm femtosecond laser pulse propagating along the x axis and polarized between the y and z axes of a KTP crystal. It was proven that the parametric amplification process by a fourth-order nonlinear polarization (chi(4)(omega(2),omega,omega,omega,-omega(1)) induces frequency generation at 480 nm, where the pump light comes from the incident laser and the seed light comes from the generated supercontinuum by filamentation. The wavelength of the generated signal could be turned from 460 to 520 nm by adjusting the propagation direction in the crystal.
