Products HomeGermanium Wedged Windows
- 30 arcminute Wedge
- Eliminate Etalon Effects and Prevent Cavity Feedback
- Uncoated and AR-Coated Germanium Substrates
- Custom Options Available
Back Reflections from Wedges Are not Collinear with the Incident Beam
(Drawing not to Scale)
WW91050
Ø1"
WW90530-E3
Ø1/2"
Please Wait
| Wedged Window Selection Guide | |
|---|---|
| Wavelength Range | Substrate Material |
| 180 nm - 8.0 µm | Calcium Fluoride (CaF2) |
| 185 nm - 2.1 μm | UV Fused Silica |
| 200 nm - 5.0 µm | Sapphire |
| 200 nm - 6.0 µm | Magnesium Fluoride (MgF2) |
| 200 nm - 11 µm | Barium Fluoride (BaF2) |
| 250 nm - 1.6 µm | UV Fused Silica for 45° AOI |
| 350 nm - 2.0 μm | N-BK7 |
| 600 nm - 16 µm | Zinc Selenide (ZnSe) |
| 1.2 - 8.0 µm | Silicon (Si) |
| 2.0 - 16 µm | Germanium (Ge) |
| V-Coated Wedged Windows | |
Features
- 30 Arcmin Wedged Windows
- Ø1/2" and Ø1" Germanium Windows Available
- Available Uncoated (2.0 - 16 µm) or with -E3 Broadband AR Coating (7 - 12 µm)
- Custom AR Coatings and Sizes Available by Contacting Tech Support
Thorlabs offers Ø1/2" and Ø1" wedged germanium (Ge) windows that are uncoated or AR-coated for 7 - 12 µm. These wedged optics eliminate fringe patterns and can be used to help avoid cavity feedback. Windows are useful for protecting a laser output from environmental effects and for beam sampling applications.
Due to its broad transmission range (2.0 - 16 µm) and opacity in the visible portion of the spectrum, germanium is well suited for IR laser applications. As shown in the Graphs tab, this substrate also acts as a longpass filter for wavelengths greater than 2 µm. In addition, germanium is inert to air, water, alkalis, and acids (except nitric acid). Germanium's transmission properties are highly temperature sensitive; in fact, the absorption becomes so large the material is nearly opaque at 100 °C and completely non-transmissive at 200 °C.
When handling optics, one should always wear gloves. This is especially true when working with germanium, as dust from the material is hazardous. For your safety, please follow all proper precautions, including wearing gloves when handling this material and thoroughly washing your hands afterward.
In addition to the germanium wedged windows offered here, Thorlabs also offers wedged windows with other substrate materials (see the selection guide above and to the right). Wedged Laser Windows with AR coatings centered around common lasing wavelengths and wedged Beam Samplers with broadband AR coatings on only one face are also available. Additionally, wedged windows with our standard AR coatings or custom sizes and thicknesses are available; please contact Tech Support for more information. We also supply planar windows with a variety of substrate materials and coating options. We also supply planar windows with a variety of substrate materials and coating options.
All of these germanium wedged windows can be ordered uncoated or with a 7 - 12 µm AR coating (designated as -E3).
Thorlabs' high-performance -E3 broadband AR coating has an average reflectance of less than 1.0% (per surface) across its specified wavelength range (denoted by the shaded blue area in the Coating graph below). The AR coating provides good performance for angles of incidence (AOI) between 0° and 30° (0.5 NA). The substrate transmission graph below shows the transmission of light through an uncoated Ge substrate. Please contact Tech Support to order optics with custom coatings or sizes.
Uncoated Ge Window
Click to Enlarge
Click for Raw Data
This graph shows the full scale measured transmission of an uncoated germanium window at normal incidence.
Click to Enlarge
Click for Raw Data
This graph shows the measured transmission of an uncoated germanium window at normal incidence in the visible wavelength range. The values reported in the visible and near infrared are limited by the noise floor of the spectrometer used. Please note that out-of-band transmission is not monitored during production and will vary from lot to lot.
Ge Window, AR Coated for 7 - 12 µm
Click to Enlarge
Click for Raw Data
This plot gives the measured reflectance (per surface) at normal incidence of our AR-coated germanium window. The average reflectance is <1.0% per surface within the shaded wavelength range of 7 µm - 12 µm.
Click to Enlarge
Click for Raw Data
Shown above is a graph of the measured transmission of a 5 mm thick AR-coated germanium substrate. The blue shaded region denotes the 7 - 12 μm spectral range where we suggest using these Ge wedged windows. For this wavelength range, the measured transmission is in excess of 90%.
| Posted Comments: | |
Eric Ma
(posted 2023-05-19 22:50:23.557) Can you make these where only one side has AR coating? It would be a good broadband beamsplitter that way. cdolbashian
(posted 2023-06-01 02:38:22.0) Thank you for reaching out to us with this inquiry. I have contacted you directly to discuss the specifics of your custom, motivation, and quantity. For future custom requests, please feel free to contact techsupport@thorlabs.com or more directly Techsales@thorlabs.com. Mohammed Alshehri
(posted 2023-01-22 20:04:25.69) Dear ThroLabs theam,
Hope you are doing well.
This is Mohammed Alshehri from NCMS.
I am enquiring about WW91050-E3 product, Is it both side coating?
We are looking for wedge germanioum with AR coating with one surface coating and the other is Grinding surface with reflection less than 1 %.
Many thanks
Best regards,
Mohammed Alshehri.
mfshehri@ncms.sa ksosnowski
(posted 2023-02-03 05:49:35.0) Hello Mohammed, thanks for reaching out to Thorlabs. For WW91050-E3 both surfaces have the same AR coating. Surface S2 also has a 30 arcmin wedge angle. Over the 7 - 12 µm range, the average reflectance for both S- and P- states is <1% per surface, and the average transmission is >94% for the whole window. The Reflection and Transmission plots and raw data can be accessed on the Graphs tab of this page. I have reached out directly to discuss this further. |
| Window Selection Guide (Table Sorted by Wavelength) | |||||
|---|---|---|---|---|---|
| Substrate and Window Type | Wavelength Range | Available AR Coatings | Reflectance over AR Coating Rangea | Transmission Data | Reflectance Data |
| Calcium Fluoride (CaF2): Flat or Wedged |
180 nm - 8.0 μm | Uncoated | - |  Raw Data |
- |
| -D Coating, 1.65 - 3.0 µm | Ravg < 1.0%; Rabs < 2.0% at 0° AOI |  Raw Data |
 Raw Data |
||
| UV Fused Silica: Flat, Wedged, V-Coated Flat, or V-Coated Wedged |
185 nm - 2.1 μm | Uncoated (Flat or Wedged) |
- |  Raw Data |
- |
| -UV Coating, 245 - 400 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C3 Coating, 261 - 266 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C6 Coating, 350 - 450 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -A Coating, 350 - 700 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -B Coating, 650 - 1050 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C Coating, 1050 - 1700 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| Sapphire: Flat or Wedged |
200 nm - 5.0 μm | Uncoated | - |  Raw Data |
- |
| -D Coating, 1.65 - 3.0 µm | Ravg < 1.0% at 0° AOI |  Raw Data |
 Raw Data |
||
| -E1 Coating, 2.0 - 5.0 µm | Ravg < 1.50%, Rabs < 3.0% (per Surface, 2.0 - 5.0 µm); Ravg < 1.75% (per Surface, 2.0 - 4.0 µm) at 0° AOI |
 Raw Data |
 Raw Data |
||
| Magnesium Fluoride (MgF2): Flat or Wedged |
200 nm - 6.0 μm | Uncoated | - |  Raw Data |
- |
| Barium Fluoride (BaF2): Flat or Wedged |
200 nm - 11 µm | Uncoated (Wedged Only) |
- |  Raw Data |
- |
| -E1 Coating, 2 - 5 µm | Ravg < 1.25%; Rabs < 2.5% at 0° AOI |  Raw Data |
 Raw Data |
||
| UV Fused Silica, for 45° AOI: Flat or Wedged |
250 nm - 1.6 µm | Coating for 250 nm - 450 nm |
Ravg < 1.0% at 45° AOI |  Raw Data |
|
| Coating for 350 nm - 1100 nm |
Ravg < 2.0% at 45° AOI |  Raw Data |
|||
| Coating for 400 nm - 700 nm |
Ravg < 1.0% at 45° AOI |  Raw Data |
|||
| Coating for 600 nm - 1700 nm |
Ravg < 1.5% at 45° AOI |  Raw Data |
|||
| Coating for 700 nm - 1100 nm |
Ravg < 1.0% at 45° AOI |  Raw Data |
|||
| Coating for 1200 nm - 1600 nm |
Ravg < 1.0% at 45° AOI |  Raw Data |
|||
| Potassium Bromide (KBr): Flat |
250 nm - 26 µm | Uncoated | - |  |
- |
| Infrasil®: Flat |
300 nm - 3 µm | Uncoated | - |  Raw Data |
- |
| N-BK7: Flat, Wedged, V-Coated Flat, or V-Coated Wedged |
350 nm - 2.0 μm | Uncoated (Flat or Wedged) |
- |  Raw Data |
- |
| -A Coating, 350 - 700 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - | Raw Data |
||
| -C7 Coating, 400 - 700 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C10 Coating, 523 - 532 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C11 Coating, 610 - 860 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -B Coating, 650 - 1050 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - | Raw Data |
||
| -C13 Coating, 700 - 1100 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| C14 Coating, 1047 - 1064 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C15 Coating, 523 - 532 nm & 1047 - 1064 nm (V-Coated) |
Ravg < 0.5% at 0° AOI | - |  Raw Data |
||
| -C Coating, 1050 - 1700 nm (Flat or Wedged) |
Ravg < 0.5% at 0° AOI | - | Raw Data |
||
| Zinc Selenide (ZnSe): Flat or Wedged |
600 nm - 16 µm | Uncoated | - |  Raw Data |
- |
| -D Coating, 1.65 - 3.0 µm | Ravg < 1.0%; Rabs < 2.0% at 0° AOI |  Raw Data |
 Raw Data |
||
| -E4 Coating, 2 - 13 µm (Only Flat) |
Ravg < 3.5%; Rabs < 6% at 0° AOI |  Raw Data |
 Raw Data |
||
| -E2 Coating, 4.5 - 7.5 µm (Only Flat) |
Ravg < 1.0%; Rabs < 2.0% at 0° AOI |  Raw Data |
 Raw Data |
||
| -E3 Coating, 7 - 12 µm (Only Wedged) |
Ravg < 1.0%; Rabs < 2.0% at 0° AOI |  Raw Data |
Raw Data |
||
| -G Coating, 7 - 12 µm (Only Flat) |
Ravg < 1% at 0° AOI |  Raw Data |
 Raw Data |
||
| Silicon (Si): Flat or Wedged |
1.2 - 8.0 μm | Uncoated | - |  Raw Data |
- |
| -E1 Coating, 2 - 5 µm (Only Wedged) |
Ravg < 1.25%; Rabs < 2.5% at 0° AOI |  Raw Data |
Raw Data |
||
| -E Coating, 3 - 5 µm (Only Flat) |
Ravg < 2% at 0° AOI |  Raw Data |
 Raw Data |
||
| Germanium (Ge): Flat or Wedged |
1.9 - 16 μm | Uncoated, 2.0 - 16 μm | - |  Raw Data |
- |
| -C9 Coating, 1.9 - 6 µm (Only Flat) |
Ravg < 2% at 0° AOI |  Raw Data |
 Raw Data |
||
| -E3 Coating, 7 - 12 µm | Ravg < 1.0%; Rabs < 2.0% at 0° AOI |  Raw Data |
Raw Data |
||
Zoom| Item # | WW90530 | WW91050 |
|---|---|---|
| Wedge Angle | 30 ± 10 arcmin | |
| Diameter | 1/2" (12.7 mm) | 1" (25.4 mm) |
| Diameter Tolerance | +0.0 / -0.2 mm | |
| Thickness | 3.0 mm | 5.0 mm |
| Thickness Tolerance | ±0.1 mm | |
| Clear Aperture | ≥Ø11.43 mm | ≥Ø22.86 mm |
| Surface Flatnessa | ≤λ/2 Over Central Ø5 mm ≤λ Over Entire Clear Aperture |
≤λ/2 Over Central Ø10 mm ≤λ Over Entire Clear Aperture |
| Surface Quality | 40-20 Scratch-Dig | |
| Wavelength Range | 2.0 - 16 µm (Uncoated) | |
| Substrate | Germaniumb | |
| Transmission Data (Click for Graph) |
Raw Data |
|
Zoom| Item # | WW90530-E3 | WW91050-E3 |
|---|---|---|
| Wedge Angle | 30 ± 10 arcmin | |
| Diameter | 1/2" (12.7 mm) | 1" (25.4 mm) |
| Diameter Tolerance | +0.0 / -0.2 mm | |
| Thickness | 3.0 mm | 5.0 mm |
| Thickness Tolerance | ±0.1 mm | |
| Clear Aperture | >Ø11.4 mm | >Ø22.9 mm |
| Surface Flatnessa | ≤λ/2 Over Central Ø5 mm ≤λ Over Entire Clear Aperture |
≤λ/2 Over Central Ø10 mm ≤λ Over Entire Clear Aperture |
| Surface Quality | 40-20 Scratch-Dig | |
| AR Coating Range | 7 µm - 12 µm (-E3 Coating) | |
| Reflectance over AR Coating Rangeb | Ravg < 1.0% (per Surface) Rabs < 2.0% (per Surface) Both Sides are Coated |
|
| Transmission over AR Coating Rangeb | Tavg > 94% Tabs > 90% |
|
| Reflectance Data (Click for Graph) |
Raw Data |
|
| Substrate | Germaniumc | |
| Transmission Data (Click for Graph) |
 Raw Data |
|
Germanium Wedged Windows