AR-Coated Entrance and Exit Faces for the Entire Wavelength Range
Our Rutile (TiO2) Polarizers offer extremely pure polarization of light with a 100 000:1 extinction ratio. They are meant for use with lasers in the 2.2 - 4 µm wavelength range and have an air-spaced design. Please note that Rutile Polarizing Prisms are designed to work with well collimated light beams. Divergent beams will produce multiple output beams.
Our Rutile Polarizing Prisms utilize a Glan-Foucault design, with two right-angle rutile prisms spaced slightly apart to create a gap. As rutile is a positively birefringent crystal, as opposed to a negatively birefringent material like calcite, the ordinary, rather than the extraordinary ray, is transmitted. When unpolarized light enters the polarizer, the beam is split into two polarized rays at the internal interface. Due to the difference in refractive indices, no and ne, the ordinary polarization component (p-polarized light) passes straight through the polarizer without deviation, while the extraordinary polarization component (s-polarized light) is deflected by total internal reflection and absorbed by the polarizer housing. The output polarization is parallel with the Polarization Axis line on the polarizer housing.
Our rutile polarizers have λ/4 polished optical faces with a Ø5 mm or Ø8 mm clear aperture. Additionally, the entrance and exit faces are AR-Coated over the entire wavelength range. They include a square aluminum housing with the polarization axis clearly marked. The GTR5 has a 9.6 mm square housing, while the GTR8 has a 15.9 mm square housing.
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The extinction ratio (ER) is the ratio of maximum to minimum transmission of a sufficiently linearly polarized input. When the transmission axis and input polarization are parallel, the transmission is at its maximum; rotate the polarizer by 90° for minimum transmission.
Polarizer Selection Guide
Thorlabs offers a diverse range of polarizers, including wire grid, film, calcite, alpha-BBO, rutile, and beamsplitting polarizers. Collectively, our line of wire grid polarizers offers coverage from the visible range to the beginning of the Far-IR range. Our nanoparticle linear film polarizers provide extinction ratios as high as 100 000:1. Alternatively, our other film polarizers offer an affordable solution for polarizing light from the visible to the Near-IR. Next, our beamsplitting polarizers allow for use of the reflected beam, as well as the more completely polarized transmitted beam. Finally, our alpha-BBO (UV), calcite (visible to Near-IR), rutile (Near-IR to Mid-IR), and yttrium orthovanadate (YVO4) (Near-IR to Mid-IR) polarizers each offer an exceptional extinction ratio of 100 000:1 within their respective wavelength ranges.
To explore the available types, wavelength ranges, extinction ratios, transmission, and available sizes for each polarizer category, click More [+] in the appropriate row below.