High-quality Brewster's angle polarizer for broadband infrared application

摘要

We have designed and constructed a linear polarizer for use with visible and infrared radiation.The broadband polarizer consists of four germanium plates arranged in a chevron geometry. Input radiation is incident near Brewster's angle for the first plate such that the reflected beam is preferentially s-wave polarized. This reflected beam is steered subsequently to the successive plates, always intersecting near Brewster's angle. The beam polarization at the output of the device is almost completely s-wave polarized. The ratio of the paraxial flux of the nearly extinguished p-wave polarized light to the s-wave polarized light transmitted through the device is found to be less than 10↑（-5） for laser illumination at wavelengths of 0.633, 1.32, 3.39, and 10.6 μm. Calculations predict that extinction ratios less than 10↑（-5） are achievable over the wavelength range .from 0.4 μm to beyond 500 μm. Alternative design geometries involving fewer plates are also described along with their advantages and disadvantages. OCIS codes: 230.5440, 260.3060, 260.5430.