Abstract:
We discuss the design and fabrication of optical filters that are transparent to a preferred linear
polarization, but are partially or substantially reflective to the orthogonal linear polarization. The
filters are fabricated by depositing thin films of form-birefringent silicon onto silicon wafers using
the serial bideposition method. Characteristic curves that are presented for the in-plane principal
refractive indices np and ns of the porous films as functions of vapor impingement angle facilitate
critical aspects of the filter design. These include matching of a p principal index and an s principal
index for films deposited at different angles, and realization of p and s principal indices that satisfy
the antireflection condition for the silicon substrate in air.
