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Features

• Ideal for Laser Cavities
• UV Fused Silica Substrate
• Available Minor Diameters: 6 mm, 8 mm, 13 mm, 16 mm, 20 mm, and 25 mm
• P-Polarized Light is Transmitted without Reflection Losses

Brewster Windows are uncoated substrates that are used as polarizers. When positioned at Brewster's Angle, the P-polarized component of the light enters and exits the window without reflection losses, while the S-polarized component is reflected. The graph to the right shows reflectance for both S- and P-polarization through UVFS at 633 nm. The 10-5 scratch-dig surface quality and λ/20 transmitted wavefront error of our Brewster windows make them an ideal choice for laser cavities.

These Brewster windows are manufactured from UV fused silica, which exhibits virtually no laser-induced fluorescence (as measured at 193 nm), making it an ideal choice for applications from the UV to the near IR. Please see the Graphs tab for a transmission plot of UV fused silica. Since the index of refraction of UV fused silica varies with wavelength, Brewster's angle is wavelength dependent; the Graphs tab contains details on this dependence.

In addition to Brewster windows, Thorlabs also offers High Precision Windows, Narrowband Laser Windows, and a complete line of polarization optics.

UV Fused Silica Transmission, Index of Refraction, and Brewster's Angle

The transmission plot below is for a 1 mm thick UV fused silica sample, including surface reflections, with the incident light normal to the surface.

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The index of refraction for UV fused silica is wavelength dependent, as shown in the graph above, and expressed by the following formula:

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Please note that that the wavelength needs to be in microns when using the formula above. Brewster's angle is given by

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Here, θ_B is Brewster's angle, n_i is the index of refraction of the incident medium (1.0003 for air), and n_t is the index of refraction of the transmitting medium (1.45701 for fused silica at 633 nm). Hence, Brewster's angle also displays a wavelength dependence, which is plotted above.