N-BK7®*
* Registered trademark of SCHOTT Glaswerke Mainz
Transmission Spectra
Refractive Index n and Internal Transmittance ti
| WL (nm) | n | ti (t=10mm) |
|---|---|---|
| 365 | 1.53627 | 0.994 |
| 404.7 | 1.53024 | 0.998 |
| 435.8 | 1.52668 | 0.999 |
| 480 | 1.52283 | 0.999 |
| 486.1 | 1.52238 | 0.999 |
| 546.1 | 1.51872 | 0.999 |
| 587.6 | 1.5168 | 0.999 |
| 589.3 | 1.51673 | 0.999 |
| 632.8 | 1.51509 | 0.999 |
| 643.8 | 1.51472 | 0.999 |
| 656.3 | 1.51432 | 0.999 |
| 706.5 | 1.51289 | 0.999 |
| 852.1 | 1.50980 | 0.999 |
| 1014 | 1.50731 | 0.999 |
| 1060 | 1.50669 | 0.999 |
| 1529 | 1.50091 | 0.997 |
Applications
- Plane and curved mirror substrates
- Windows and spherical lenses
- All with any type of coating (HR, PR, AR) for the wavelength range given in the table
- All transmittive components are selected to be free of bubbles and inclusions
Properties
- High transmission from VIS to NIR
- Very good homogeneity
Optical Data
- Homogeneity (dn): Standard: < 2 x10-5, On request: down to 1 x 10-6
- Max. bubble diameter: < 0.1 mm
- Max. cross section of bubbles in 100 cm³ of glass: < 0.03 mm²
- Max. cross section of inclusions in 100 cm³ of glass: < 0.03 mm²
Mechanical Data
- Density: 2.51 g/cm³
- Young modulus: 82 GPa
- Poisson ratio: 0.206
Thermal Data
- Thermal linear expansion coefficient: -30...+70°C: 7.1 x 10-6 K-1 | +20...+300°C: 8.3 x 10-6 K-1
- Specific heat capacity: 858 J/(kg?K)
- Thermal conductivity: 1.114 W/(m?K)
- Melting point: 559 °C
