The length scale of
such variation, or their lattice parameter, determines the
modulated spectral wavelength. For the photons with frequencies
falling in the band gap of the PCs, the light can be
totally reflected regardless its incidence direction, allowing it
to propagate only along a specific direction, or even confining
them within a specified volume. Utilizing optical and
electron lithography, some complex photonic structures have
been fabricated with one-, two-, and even three-dimensional
structures.2 However, due to the limitation of the hierarchical
structures that can be created via lithography, the manmade
PCs and their working wavelength ranges are rather limited