Beam displacing prisms are used to separate an input beam into two orthogonally polarized output beams and can be used as polarizing beamsplitters in applications where the 90° separation generated by polarizing beamsplitter cubes is not desired. Fabricated from yttrium orthovanadate (YVO4), these beam displacers provide a beam separation of 1.2 mm at a wavelength of 2000 nm and can be used with wavelengths from 488 nm to 3.4 μm (see Graphs tab). This beam separation sets an upper limit to the beam size that is appropriate for use with these polarizers. Our D-shaped mirrors are ideal for picking off one of the two polarized beams.
These YVO4 beam displacers are available uncoated or with a V coating that provides <0.25% reflectance at 2000 nm (see the Graphs tab). The BDY12 and BDY12-2000 beam displacers are mounted in Ø1/2" anodized aluminum housings for compatibility with our Ø1/2" lens tubes and Ø1/2" rotation mounts, while the BDY12U and BDY12U-2000 beam displacers are unmounted 12.0 mm x 6.0 mm x 4.0 mm (0.47" x 0.24" x 0.16") optics. All of these beam displacers produce output beams that are parallel to each other to within 30 arcsec.
Click to Enlarge Click Here for Raw Data Reflectance for the BDY12-2000 and BDYU12-2000 Beam Displacers
Click to Enlarge Click Here for Raw Data The linear separation between the orthogonally polarized output beams varies with wavelength.
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.
Schematic of the BDY12U Unmounted YVO4 Beam Displacer
Unmounted YVO4 Beam Displacers
Produces Two Orthogonally Polarized Output Beams
Available Uncoated or V-Coated at 2000 nm
These Unmounted Beam Splitters are compact [0.47" x 0.24" x 0.16" (12.0 mm x 6.0 mm x 4.0 mm)], making them ideal for use in OEM applications. They split an input beam into two output beams with orthogonal polarization. The uncoated beam splitter provides excellent transmission from 488 nm to 3.4 µm, while the 2000 nm V-coat minimizes the reflectance at 2000 nm. The line on the beam splitter indicates the optic axis. They can be mounted in a kinematic platform mount or a tip, tilt, and rotation stage.
These Mounted Beam Splitters are seated in Ø1/2" anodized aluminum housings. This housing fits inside our Ø1/2" lens tubes, making them compatible with our Ø1/2" rotation mounts. These beam splitters split an input beam into two output beams with orthogonal polarization. The uncoated beam splitter provides excellent transmission from 488 nm to 3.4 µm, while the 2000 nm V-coat minimizes the reflectance at 2000 nm.