Giant birefringence in anisotropically nanostructured silicon

We performed a study of the in-plane birefringence of anisotropically nanos tructured Si layers, which exhibit a greater difference in the main value o f the anisotropic refractive index than that of natural birefringent crysta ls. The anisotropy parameters were found to be strongly dependent on the ty pical size of the Si nanowires used to assemble the layers. This finding op ens the possibility of an application of birefringent Si retarders to a wid e spectral range for control of the polarization state of light. (C) 2001 O ptical Society of America.