Summary: Laser & Photon. Rev. 4, No. 3, 355373 (2010) / DOI 10.1002/lpor.200910006 355
Abstract Quadratic nonlinear photonic crystals are materials
in which the second order susceptibility is spatially mod-
ulated while the linear susceptibility remains constant. These
structures are significantly different than the more common pho-
tonic crystals, in which the linear susceptibility is modulated.
Nonlinear processes in nonlinear photonic crystals are governed
by the phase matching requirements, which are determined by
the reciprocal lattice of these crystals. Therefore, the modulation
of the nonlinear susceptibility enables to engineer the spatial
and spectral response in various three-wave mixing processes.
It enables to support the efficient generation of new optical fre-
quencies at multiple directions. We analyze three wave mixing
processes in nonlinear photonic crystals in which the modula-
tion is either periodic, quasi-periodic, radially symmetric or even
random. We discuss both one-dimensional and two-dimensional
modulations. In addition to harmonic generations, we outline
several new possibilities for all-optical control of the spatial and
polarization properties of optical beams in specially designed
nonlinear photonic crystals.