Fabrication of spatial walk-off polarizing films by oblique deposition

A spatial walk-off polarizer that utilizes form-birefringence in an obliquely deposited thick film is proposed. The film is composed of two substances, slant needle-like microcolumns and resultant fine voids around them. The structure has the uniaxial birefringence whose optic axis is parallel to the column/void axis. The basic operation was confirmed with tantalum-oxide thick films deposited onto beveled silica substrates. The spatial walk-off characteristic has clearly been observed, and the maximum polarization-split angle is measured to be 7.3/spl deg/, being larger than that of existing polarizers such as those made of rutile and calcite.<
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