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Material data of BK7 Schott glass

Transmission Spectrum of BK7 Schott glass windows (3 mm thickness)

Refractive index n and internal transmittance ti Wavelength [nm] n ti (t=5mm) 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