Vacuum Compatible Fused Silica Optical Ports


  • Fused Silica Optical Ports with Brewster or Wedged Windows
  • Uncoated UV Fused Silica Windows for 185 nm to 2.1 μm
  • Can be Used at Pressures from 10-7 Torr to 5 psi at 25 °C

GC05WP

Wedged Window Optical Port

GC05BP

Brewster Window Optical Port

Application Idea

A GC05BP Optical Port can be fitted into a KF25C050 Flange for integration into a vacuum system.

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Back View of VRC1CPTClick to Enlarge
A GC05WP Wedged Optical Port Secured in a KF25C050 Vacuum Flange

Features

  • Couple Beams Into and Out of Vacuum Systems
  • Suitable for Vacuum Pressures as Low as 10-7 Torr at 25°C
  • Compatible with Our KF25 and KF16 Flange to Compression Fitting Adapters for Ø1/2" (Ø12.7 mm) Pipes and Tubes
  • Custom Fused Silica Optical Ports Available by Contacting Tech Support

Thorlabs' Fused Silica Optical Ports provide a solution for coupling beams into or observing processes inside of a vacuum chamber. The GC05BP optical port has a BW1302 Brewster window fused at its designed Brewster's angle of 55.5°, enabling it to transmit the p-polarized component of light with near-zero reflection losses. The GC05WP optical port is sealed with a WW40530 wedged window that has a 30 arcmin wedge to eliminate fringe patterns and reduce etalon effects. 

The vacuum port windows are made from UV fused silica (UVFS), a durable material that resists chipping and cracking and offers high transmission for wavelengths between 185 nm and 2.1 μm. We used vacuum and Helium leak testing to ensure that both of the ports offered below are capable of withstanding vacuum environments as low as 10-7 Torr and pressures as high as 5 psi at 25 °C. Post production, the ports undergo ultrasonic cleaning, a methanol rinse, and are coated with First Contact™* Polymer, a polymer coating that protects the the optic from scratching and chipping and can be easily peeled off before the optical port is used. The ports are not vacuum sealed when shipped; before using the ports in a vacuum setup, we advise users to clean with a methanol rinse.

The OD of these ports is Ø1/2" (Ø12.7 mm), allowing them to be integrated into KF16 and KF25 vacuum systems using the KF16C050 and KF25C050 flange to compression fitting adapters, respectively. A glass rib, made from heating the ports and pushing them onto themselves, circles the ports and ensures that there is no movement under vacuum when the ports are installed in compression fittings. 

For custom optical ports, including alternative windows and coatings, please contact Tech Support.

*First Contact is a trademark of Photonic Cleaning Technologies, LLC.

UV Fused Silica Transmission

Brewster Angle for Air to UVFS
Click to Enlarge
Click Here for Raw Data
Transmission of 10 mm Thick, Uncoated UV Fused Silica

UV Fused Silica Index of Refraction and Brewster's Angle

UVFS Brewster Angle
Click to Enlarge

This graph shows the calculated reflectance of uncoated UV fused silica for polarized light as a function of angle of incidence. The reflectance for P-polarized light goes to zero at Brewster's angle.
UVFS Index of Refraction
Click to Enlarge

This graph shows the calculated index of refraction of UV fused silica as a function of wavelength.
Brewster Angle for Air to UVFS
Click to Enlarge

This graph shows the calculated value of Brewster's angle as a function of wavelength when light is passing from air to UV fused silica.

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

Index of Refraction for Fused Silica wavelength dependency.

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

Brewster's Angle Equation.

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, as shown in the plot above.

Polarization through a Brewster Window
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

Brewster windows are typically used as polarizers within laser cavities. 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 essentially acts as a polarizer.

Brewster's angle is given by

Brewster's Angle Equation

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

Index of Refraction for Fused Silica wavelength dependency.

Please note that that the wavelength needs to be in microns when using the formula above.


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UV Fused Silica Brewster Window Optical Port

Item # GC05BP
Window BW1302
Minor Diameter 13.0 mm
Minor Diameter Tolerance +0.0 / -0.1 mm
Thickness 2.0 mm
Thickness Tolerance ±0.1 mm
Brewster Angle 55.5° 32' @ 633 nm
Minor Axis Diameter 0.51" (13.0 mm)
Clear Aperture >Ø8 mm (Minor Axis)
Parallelism ≤5 arcsec
Transmitted Wavefront Errora <λ/10 @ 633 nm
Over Clear Aperture
Surface Quality 20-10 Scratch-Dig
Wavelength Range 185 nm - 2.1 μm (Uncoated)
Reflectance vs AOIa
Transmission Data
(Click for Graph)
Uncoated UVFS Transmission
Raw Data
Substrate UV Fused Silicab
Usage Pressure Range 10-7 Torr to 5 psi @ 25 °C
  • Measured at 633 nm
  • Click Link for Detailed Specifications on the Substrate
  • UV Fused Silica Window Sealed at Brewster's Angle (55.5° for 633 nm)
    • Near-Zero Reflection Losses of P-Polarized Light
  • Fused Silica Tube with Ø1/2" Outer Diameter
  • Suitable for Use at Pressures from 10-7 Torr to 5 psi at 25 °C

Thorlabs' GC05BP Optical Port is sealed at a 55.5° angle with a BW1302 Uncoated Brewster Window (see table to the right), enabling near-zero reflection losses of the p-polarized component of an incident beam while supressing transmission of s-polarized light (see Brewster Windows tab for more information). Its Ø0.50" (Ø12.7 mm) outer diameter tube is compatible with our KF16C050 and KF25C050 flange to compression fitting adapters, enabling easy integration into KF16 and KF25 vacuum systems, respectively. A glass rib circling the port 0.77" (19.5 mm) from its open end ensures that there is no movement under vacuum when the port is installed in a compression fitting.

Brewster Angle for Air to UVFSClick to Enlarge
The image above shows the reflection of some S-polarized light and the transmission of P-polarized light with near-zero reflection losses through a Brewster window. 
Brewster Angle for Air to UVFS
Click to Enlarge

This graph shows the calculated Brewster's angle as a function of wavelength when light is passing from air to UV fused silica.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
GC05BP Support Documentation
GC05BPCustomer Inspired! Optical Viewport with Uncoated UV Fused Silica Brewster Window
$200.00
Today

UV Fused Silica Wedged Window Optical Port

Item # GC05WP
Window WW40530
Wedge Angle 30 ± 10 arcmin
Diameter 1/2" (12.7 mm)
Diameter Tolerance +0.0 / -0.2 mm
Thickness 3.0 mm
Thickness Tolerance ±0.4 mm
Clear Aperture >Ø8 mm
Surface Flatnessa ≤λ/20 Over Central Ø5 mm
≤λ/10 Over Full Clear Aperture
Surface Quality 10-5 Scratch-Dig
Wavelength Range 185 nm - 2.1 μm (Uncoated)
Transmission Data
(Click for Graph)

Raw Data
Substrate UV Fused Silicab
Usage Pressure Range 10-7 Torr to 5 psi @ 25 °C
  • Measured at 633 nm
  • Click Link for Detailed Specifications on the Substrate
  • Window has 30 arcmin Wedge to Eliminate Fringe Patterns and Reduce Etalon Effects
  • Fused Silica Tube with Ø1/2" Outer Diameter
  • Suitable for Use at Pressures from 10-7 Torr to 5 psi at 25 °C

Thorlabs' GC05WP Optical Port is sealed with a WW40530 Uncoated Wedged Window (see table to the right), which has a 30 arcmin wedge to eliminate fringe patterns and reduce etalon effects. Its Ø0.50" (Ø12.7 mm) outer diameter is compatible with our KF16C050 and KF25C050 flanges, enabling easy integration into KF16 and KF25 vacuum systems, respectively. A glass rib circling the port 0.63" (17.0 mm) from the open end ensures that there is no movement under vacuum when the port is installed in a compression fitting.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
GC05WP Support Documentation
GC05WPCustomer Inspired! Optical Viewport with Uncoated UV Fused Silica Wedged Window
$120.00
Today