Form birefringence in intrinsic birefringent media possessing a subwavelength structure.

We theoretically investigate optical birefringence originating from subwavelength structures in intrinsic birefringent media. Assuming alternating layers of isotropic and anisotropic materials, the propagation of optical waves is simulated on the basis of the finite difference time domain method. Optical polarization changes throughout the structure reveal the birefringence of the layered structure as a whole. In addition, the birefringence is also analyzed on the basis of effective medium theory. The results indicate that the optical birefringence of the structure as a whole can be modified by the magnitude and direction of the intrinsic birefringence of the anisotropic layers. This theoretical prediction will be useful for micro- and nanofabrication in optical devices.