- 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.
|Item #|| BW0601 || BW0801 || BW0802 || BW1302 || BW1602 ||BW2002||BW2502|
|Minor Diameter|| 6.0 mm || 8.0 mm || 8.0 mm || 13.0 mm || 16.0 mm ||20.0 mm||25.0 mm|
|Thickness|| 1.0 mm || 2.0 mm|
|Material||UV Fused Silica|
|Thickness Tolerance||±0.1 mm||±0.2 mm||±0.1 mm|
|Surface Quality||10-5 Scratch-Dig|
|Transmitted Wavefront Error||<λ/20|
|Brewster Angle||55° 32' @ 633 nm|
|Minor Axis Tolerance||+0.00/-0.10 mm||+0.00/-0.13 mm||+0.00/-0.10 mm|
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.
The index of refraction for UV fused silica is wavelength dependent, as shown in the graph above, and expressed by the following formula:
Please note that that the wavelength needs to be in microns when using the formula above. Brewster's angle is given by
Here, θB is Brewster's angle, ni is the index of refraction of the incident medium (1.0003 for air), and nt 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.