Brewster Window Optic Mounts
- Mount Brewster Windows at Brewster's Angle
- Design Maximizes Clear Aperture of Window
- Compatible with Ø1/2" or Ø1" Smooth-Bore Mounts
or Internally SM1-Threaded Components
BW16M with SM1P1 Adapter
for use in a KS1RS Kinematic
Compatible with Internally
Click to Enlarge BW2502 Brewster Window in Our BW25M Mount with a KS1RS Kinematic Rotation Mount (No Adapter Necessary)
Click to Enlarge BW1602 Brewster Window in Our BW16M Mount with an SM1P1 Thread Adapter and KS1RS Kinematic Rotation Mount
Click to Enlarge BW0802 Brewster Window in Our BW08M2 Mount with an SM05P05 Thread Adapter and KS05RS Kinematic Rotation Mount
- Holds Brewster Windows with 8 mm, 13 mm, 16 mm, 20 mm, or 25 mm Minor Diameters
- Steel Flexure Retention Plates for Holding Optics
- Exit Port for Reflected S-Polarized Light Allows Use in Either Direction
- Directly Compatible with Ø1/2" or Ø1" Smooth-Bore Mounts or Internally SM1-Threaded Components
Thorlabs' Brewster Window Optic Mounts provide a stable and convenient mounting solution for our line of UV fused silica Brewster windows. These mounts are engineered with a 55° 32’ mounting angle (Brewster’s Angle at 633 nm) that allows for the transmission of p-polarized light while reflecting s-polarized light. To accommodate other wavelengths, these mounts can be attached to a kinematic mount. Our kinematic rotation mounts are particularly well suited for our Brewster windows as they provide adjustment for the reflected beam; please see the table below for compatible kinematic rotation mounts. For information concerning Brewster's angle at other wavelengths, please see the Brewster Window tab.
We offer mounting options for 8 mm (1 or 2 mm thick optic), 13 mm (2 mm thick optic), 16 mm (2 mm thick optic), 20 mm (2 mm thick optic), and 25 mm (2 mm thick optic) minor-axis-length Brewster windows (see the table below for further information). An exit port is provided for the reflected s-polarized light so that the mount may be used in either direction.
The Brewster windows are held in place using a steel flexure retention plate and three locking screws. For the BW08M1 and BW08M2, these locking screws require a 0.035" hex key. For the BW13M, BW16M, BW20M, and BW25M, these locking screws require a 0.05" hex key.
|Item #||Compatible Brewster Window||Compatible Kinematic Rotation Mount|
|Minor Axis Length||Thickness||Item #||Required Adapter Item #||Item #|
|BW08M1||8 mm||1 mm||BW0801||SM05P05||KS05RS|
|BW08M2||8 mm||2 mm||BW0802||SM05P05||KS05RS|
|BW13M||13 mm||2 mm||BW1302||SM1P1||KS1RS|
|BW16M||16 mm||2 mm||BW1602||SM1P1||KS1RS|
|BW20M||20 mm||2 mm||BW2002||SM1P1||KS1RS|
|BW25M||25 mm||2 mm||BW2502||Not Applicablea||KS1RS|
The image above shows the reflection of s-polarized light and transmission of p-polarized light through a Brewster window. Some s-polarized light will be transmitted through the window.
Brewster Windows are uncoated substrates that are used as polarizers, typically within a laser cavity. When positioned at Brewster's Angle (55° 32' at 633 nm), the p-polarized portion of the light will pass through the window with no losses, while a fraction of the s-polarized portion will be reflected off the Brewster window. When used in a laser cavity, the Brewster window acts essentially as a polarizer.
Brewster's angle is given by
θB is Brewster's angle.
ni is the index of refraction of the incident medium, which is 1.0003 for air.
nt is the index of refraction of the transmitting medium, which is 1.45701 for fused silica at 633 nm
It should be noted that the index of refraction is wavelength dependent. For fused silica, the index of refraction can be expressed as
Please note that that the wavelength needs to be in microns when using the formula above.