Polarization-sensitive subwavelength antireflection surfaces on a semiconductor for 975 nm

We present the results of subwavelength antireflection surfaces etched into GaAs for use at 975 nm. These surfaces comprise linear gratings with periods less than the wavelength of light in GaAs. The structure appears as a homogeneous birefringent film. For one of the two polarizations, the film is directly analogous to the well-known quarter-wavelength antireflection coating. For the other polarization there is little effect on the surface reflectivity.