BK7 Window
BK7 windows are Schott borosilicate materials used for optical applications ranging from the visible to near-infrared spectrum.
Description
BK7 window is the most common type of window. It has good performance over visible and near infrared wavelength regions. At the same time, BK7 window is ideal for applications require minimal transmitted beam deviation. It is suitable for AR coating.
Advantages:
- Clear and uniform color; Almost no bubbles or inclusions;
- High purity and excellent uniformity;
- Superior chemical resistance and stain resistance;
- Excellent transmission in the visible and near-infrared spectrum;
- Low visible light absorption with uniform transmittance.
Specifications:
| Diameter Tolerance: | +0.0/-0.2mm |
| Thickness Tolerance: | ±0.2mm / ±0.005 |
| Clear Aperture: | >85%, >95% |
| Parallelism: | 3 min, 3 sec |
| Surface Quality: | 60-40, 10-5 |
| Flatness: | λ/2, λ/8, λ/10 |
| Bevel Protective: | <0.25mm X 45° |
| Coating: | Optional |
N-BK7 Windows:
1.Customized N-BK7 windows ranging from ∅2.0mm to 200mm are available.
2.In addition to circular shapes, square or other polygonal shapes can also be provided
3.with 100% clear aperture achievable upon request.
4.Chamfers of any size and angle can be fabricated according to customer drawings.
5.Anti-reflection coatings, high-reflection coatings, and other coating systems are available.
High Precision Round BK7 Window:
Specifications
| Specification | Value |
|---|---|
| Material | BK7 |
| Diameter Tolerance | +0.0 / -0.2 mm |
| Thickness Tolerance | ±0.2 mm |
| Clear Aperture | >90% |
| Parallelism | <10 arc seconds |
| Surface Quality | 20-10 |
| Flatness | <λ/10 @ 633 nm per 25 mm |
| Bevel Protective | <0.5 mm × 45° |
| Model | Material | Diameter (mm) | Thickness (mm) |
|---|---|---|---|
| E-WGP-001000635-BK7-A | BK7 | 10 | 6.35 |
| E-WGP-001270635-BK7-A | BK7 | 12.7 | 6.35 |
| E-WGP-001500635-BK7-A | BK7 | 15 | 6.35 |
| E-WGP-002000635-BK7-A | BK7 | 20 | 6.35 |
| E-WGP-002540635-BK7-A | BK7 | 25.4 | 6.35 |
| E-WGP-003000635-BK7-A | BK7 | 30 | 6.35 |
| E-WGP-003810635-BK7-A | BK7 | 38.1 | 6.35 |
| E-WGP-005080635-BK7-A | BK7 | 50.8 | 6.35 |
Standard Round BK7 Coated Window
| Specification | Value |
|---|---|
| Material | BK7 |
| Dimension Tolerance | +0.0 / -0.2 mm |
| Thickness Tolerance | ±0.2 mm |
| Surface Quality | 60 / 40 |
| Clear Aperture | >90% |
| Wavefront Distortion | <λ/8 @ 633 nm per 25 mm |
| Parallelism | <30 arc seconds |
| Chamfer | Protected <0.5 mm × 45° |
| Coating | Narrow band: R < 0.25% per surface, AOI = 0° Broadband: R < 0.5% per surface, AOI = 0° |
| Damage Threshold | BK7: > 5 J/cm², 20 ns, 20 Hz, @ 1064 nm |
| Model | Material | Diameter (mm) | Thickness (mm) | Coating Wavelength (nm) |
|---|---|---|---|---|
| E-WGP-001270300-BK7-V1 | BK7 | 12.7 | 3 | 515–532 |
| E-WGP-002540635-BK7-V1 | BK7 | 25.4 | 6.35 | 515–532 |
| E-WGP-005080635-BK7-V1 | BK7 | 50.8 | 6.35 | 515–532 |
| E-WGP-001270300-BK7-V2 | BK7 | 12.7 | 3 | 630–650 |
| E-WGP-002540635-BK7-V2 | BK7 | 25.4 | 6.35 | 630–650 |
| E-WGP-005080635-BK7-V2 | BK7 | 50.8 | 6.35 | 630–650 |
| E-WGP-001270300-BK7-V3 | BK7 | 12.7 | 3 | 780–810 |
| E-WGP-002540635-BK7-V3 | BK7 | 25.4 | 6.35 | 780–810 |
| E-WGP-005080635-BK7-V3 | BK7 | 50.8 | 6.35 | 780–810 |
| E-WGP-001270300-BK7-V4 | BK7 | 12.7 | 3 | 1028–1064 |
| E-WGP-002540635-BK7-V4 | BK7 | 25.4 | 6.35 | 1028–1064 |
| E-WGP-005080635-BK7-V4 | BK7 | 50.8 | 6.35 | 1028–1064 |
| E-WGP-001270300-BK7-V5 | BK7 | 12.7 | 3 | 515–532 & 1028–1080 |
| E-WGP-002540635-BK7-V5 | BK7 | 25.4 | 6.35 | 515–532 & 1028–1080 |
| E-WGP-005080635-BK7-V5 | BK7 | 50.8 | 6.35 | 515–532 & 1028–1080 |
| E-WGOP-001270300-BK7-V6 | BK7 | 12.7 | 3 | 400–700 |
| E-WGP-002540635-BK7-V6 | BK7 | 25.4 | 6.35 | 400–700 |
| E-WGP-005080635-BK7-V6 | BK7 | 50.8 | 6.35 | 400–700 |
| E-WGP-001270300-BK7-V7 | BK7 | 12.7 | 3 | 650–1100 |
| E-WGP-002540635-BK7-V7 | BK7 | 25.4 | 6.35 | 650–1100 |
| E-WGP-005080635-BK7-V7 | BK7 | 50.8 | 6.35 | 650–1100 |
FAQs
1. What is your MOQ for BK7 Window?
Our standard MOQ is 50 pieces for regular production.
For small orders (≤50 pcs), we can still accept production and provide full inspection reports and measurement data for each piece upon request.
2. Do you support small batch or prototype orders?
Yes. We support small batch and prototype production for testing and evaluation before mass production.
3. What is your production lead time?
- Standard polished fused silica windows: 4–5 weeks
- Coated optical windows (AR / HR): 5–6 weeks, depending on coating type and specifications
4. Do you provide inspection reports?
Yes. We provide quality inspection reports based on order quantity:
- ≤50 pcs: Full inspection data for each piece available
- 100–1,000 pcs: 5%–10% random sampling inspection reports
- >1,000 pcs: 0.5% sampling inspection reports
All inspection data includes dimensional and surface quality parameters.
5. What coating options are available?
We offer:
- Anti-Reflection (AR) coatings
- High-Reflection (HR) coatings
- Broadband coatings
- Custom wavelength coatings (UV / Visible / IR)
6. Can you manufacture custom sizes and shapes?
Yes. We support OEM manufacturing according to drawings.
Available shapes include:
- Round
- Square
- Rectangular
- Stepped
- Wedged
- Drilled / special structures
7. What quality certifications do you have?
We are certified under international quality management systems, including:
- ISO 9001 Quality Management System
- IATF 16949 Automotive Quality System
- Good Standardization Practices Certification
We also apply strict internal quality control processes, including dimensional inspection, surface quality testing, and coating performance verification before shipment.
Coating
Uncoated N-BK7 Typical Transmission
Coating solutions offered by Elyon
- Anti-Reflection Coating (AR / BBAR)
(1) Single-layer Magnesium Fluoride (MgF₂) AR Coating
visible spectrum (400–700 nm). Single-side reflectance is controlled below 1.5%。
(2) Standard Multi-layer Broadband AR Coating
A-type coating: 350~700 nm visible range, average reflectance＜0.5%
B-type coating: 650~1100 nm near-infrared band
AB broadband coating: 400~1100 nm (VIS+NIR dual band)
C-type coating: 1050~1700 nm SWIR
(3) Single-Wavelength V-type Narrowband AR Coating
Custom coating for discrete laser wavelengths: 405/488/532/632.8/808/1064 nm, reflectance＜0.25% at target wavelength
2. High-Reflection Coating
(1) Metallic HR Coatings (Aluminum / Silver / Gold with protective overcoat)
Aluminum (Al) coating: 400 nm ~ 2 μm, reflectance＞90% in visible spectrum, covered with SiO
Silver (Ag) coating: 500 nm ~ 2 μm, reflectance＞95% for VIS & NIR
Gold (Au) coating: 700 nm ~ 2 μm, reflectance＞98% in near-infrared
(2) All-Dielectric Multi-layer HR Coating (High Laser Damage Threshold for Laser Application)
Visible HR coating: 450~700 nm average reflectance＞99.5% or single wavelength HR at 532 nm
NIR HR coating: ＞99.8% reflectance at 808/1064/1310/1550 nm
