Adjustable optical anisotropy in porous GaAs

We report a theoretical investigation of the optical properties of porous (100) GaAs having crystallographic pores. An effective medium approach is used for the calculations. A biaxial anisotropy of the material is predicted for most of the material parameters. The parameter windows for different kinds of uniaxial anisotropy are predicted as well. It is shown that the type and value of the optical anisotropy, and even the direction of the optical axes, can be controlled by GaAs etching parameters, and this letter gives the theoretical blueprint for the overall pore morphology required for that.