Open AccessOdd harmonics-enhanced supercontinuum in bulk solid-state dielectric medium
Author(s) -
N. Garejev,
Vytautas Jukna,
G. Tamošauskas,
M. Veličkė,
Rosvaldas Šuminas,
Arnaud Couairon,
A. Dubietis
Publication year - 2016
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.017060
Subject(s) - supercontinuum , filamentation , optics , harmonics , wavelength , physics , self phase modulation , pulse compression , materials science , nonlinear optics , laser , photonic crystal fiber , telecommunications , radar , quantum mechanics , voltage , computer science
We report on generation of ultrabroadband, more than 4 octave spanning supercontinuum in thin CaF 2 crystal, as pumped by intense mid-infrared laser pulses with central wavelength of 2.4 μm. The supercontinuum spectrum covers wavelength range from the ultraviolet to the mid-infrared and its short wavelength side is strongly enhanced by cascaded generation of third, fifth and seventh harmonics. Our results capture the transition from Kerr-dominated to plasma-dominated filamentation regime and uncover that in the latter the spectral superbroadening originates from dramatic plasma-induced compression of the driving pulse, which in turn induces broadening of the harmonics spectra due to cross-phase modulation effects. The experimental measurements are backed up by the numerical simulations based on a nonparaxial unidirectional propagation equation for the electric field of the pulse, which accounts for the cubic nonlinearity-induced effects, and which reproduce the experimental data in great detail.