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Updated: Jul 4, 2026

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
Published on: April 25, 2019
Wavelength femtosecond light pulse generated from filamentation-assisted fourth-order nonlinear process in potassium
Xipeng Zhang1, Hongbing Jiang, Li Chen
1Department of Physics and State Key Laboratory for Mesoscopic Physics, Peking University, Beijing, China.
Abstract:
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.
