
Investigation of phase matching for third-harmonic generation in silicon slow light photonic crystal waveguides using Fourier optics
Author(s) -
Christelle Monat,
Christian Grillet,
Bill Corcoran,
David Moss,
Benjamin J. Eggleton,
Thomas P. White,
Thomas F. Krauss
Publication year - 2010
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.18.006831
Subject(s) - optics , nonlinear optics , photonic crystal , physics , dispersion (optics) , second harmonic generation , fourier transform , optoelectronics , materials science , laser , quantum mechanics
Using Fourier optics, we retrieve the wavevector dependence of the third-harmonic (green) light generated in a slow light silicon photonic crystal waveguide. We show that quasi-phase matching between the third-harmonic signal and the fundamental mode is provided in this geometry by coupling to the continuum of radiation modes above the light line. This process sustains third-harmonic generation with a relatively high efficiency and a substantial bandwidth limited only by the slow light window of the fundamental mode. The results give us insights into the physics of this nonlinear process in the presence of strong absorption and dispersion at visible wavelengths where bandstructure calculations are problematic. Since the characteristics (e.g. angular pattern) of the third-harmonic light primarily depend on the fundamental mode dispersion, they could be readily engineered.