BK7 Windows/Rods
BK7 is borosilicate crown optical glass with an excellent physical and chemical properties for applications in visible and near IR. Large BK7 glass with high homogeneity, low bubble and inclusion content can be produced at a large quantity and at low cost, making it the standard material for optical components (uncoated or coated) in visible and IR.
Newlight Photonics offers circular/rectangular BK7 windows or rods with thickness from 0.15 mm to 150 mm.
Various high quality HR, AR, and partial reflective coatings are available upon request.
| Part No. | Aperture | Thickness | Coating | Price | Availability | Add to Cart |
Basic Properties of BK7 and N-BK7 Glass:
|
|
BK7, N-BK7 |
| Transparency Range | 360 - 2000 nm |
| Density | 2.51 g/cm3 |
| Thermo-Optic Coefficients (dn/dT) |
2.3 x 10-6 /oC |
| Optical Homogeneity | Δn < 10-6 /cm |
| Mohs Hardness | ~ 6 |
| Thermal Conductivity | 1.1 W/m/K |
| Thermal Expansion Coefficients |
8 x 10-6 /K (BK7), 7.1 x 10-6 /K (N-BK7) |
| Sellmeier Equations (λ in µm) |
n2=1+1.03961λ2/(λ2- 0.0060007)+0.23179λ2/(λ2-0.020018)+1.01047λ2/(λ2-103.5600) |
| Wavelength(nm) | Index of Refraction |
| 400 | 1.5308 |
| 532 | 1.5194 |
| 632.8 | 1.5150 |
| 1064 | 1.5066 |
Transmission curve:
Specifications of BK7 Windows:
| Dimension Tolerance: | Diameter: ± 0.1 mm, Thickness: ± 0.1 mm (T=<5mm), +0.5/-0.1 mm (T>5mm) |
| Clear Aperture: | > 85% |
| Surface Quality: | 20/10 Scratch and Dig |
| Parallelism: | < 1 arc min |
| Flatness: | λ/8 @ 632.8 nm for T>=2mm |
| Transmission Wavefront Distortion: | < λ/8 @ 632.8 nm for T=<25mm < λ/8 @ 632.8 nm per 25mm for T>25mm |
| Bevel: | < 0.25 mm X 45° |
N-BK7, the ROHS version of standard BK7 may be used for the windows without notice. N-BK7 will always be used for EU customers in compliance with the RoHS regulations. Please let us know if N-BK7 and BK7 have to be distinguished for your applications.
Coatings:
Various high quality HR, AR, Broadband AR (BBAR) and partial reflective (PR) coatings are also available upon request.
AR Coatings: R<0.2% at the central wavelength
HR Coatings: R>99.6% at the central wavelength
PR Coatings: R=3-95% at the specified wavelength
Broadband AR: R<1% over the specified range
If you do not find the suitable products above, you may let us know your requirements or applications in the form below. Our sales or technical staff will get back to you as soon as possible.
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