Etched Bragg reflectors as two-dimensional photonic crystals

We have studied GaAs/oxidized AlAs (AlOx) Bragg reflectors with etched air grooves running parallel to the growth direction. Such structures possess periodic modulation of the refractive index in two dimensions, and we have found that they have a photonic band gap for E-polarized modes over a large range of parameters of the structure, and can support complete photonic band-gaps for both E- and H-polarizations for a more restricted range of values of the parameters. Also, for certain parameter values of the etched Bragg reflector, the total density of states in a wide spectral region is reduced by factor of up to 20 compared to an effective medium characterized by the mean dielectric constant.