Three-dimensional photon confinement in photonic crystals of low-dimensional periodicity

Photonic crystals of one- or two-dimensional periodicity can be used to achieve three-dimensional photon confinement in dielectric waveguides with modal volumes of the order of a cubic half-wavelength. Since photonic crystals of low-dimensional periodicity do not have full three-dimensional bandgaps. The microcavities undergo increasing radiation losses with decreasing modal volumes. High-𝒬 resonant modes can be generated by reducing the strength of the photon confinement. Increasingly, larger modal volumes lead to lower radiation losses and more efficient coupling to waveguide modes outside the cavity