BK3 by Sumita

Obsolete Very Rare Environmentally Dangerous
Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.27–2.0 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.27–2.0 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.280–2.000 µm
Optical Properties
Refractive Index (nd) 1.49831
Abbe Number (Vd) 65.1
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.2178 - 0.0100476\,\lambda^2 + 0.0102379\,\lambda^{-2} + 0.000113305\,\lambda^{-4} - 7.33265 \times 10^{-7}\,\lambda^{-6} + 2.57691 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K)
TCE 100/300°C (10-6/K) 6.5
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 2.36
Relative Cost
Mechanical Properties
Young's Modulus (GPa)
Poisson's Ratio
Knoop Hardness (kgf/mm²)
Chemical Resistance
Climatic Resistance 2
Stain Resistance
Acid Resistance 4
Alkali Resistance
Phosphate Resistance
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd
BSC3 Hoya 1.498309 65.130542
BK3 Schott 1.498311 65.063609
BSL3 Ohara 1.498308 65.026785
H-K3 CDGM 1.50463 64.720718
BSC4 Hoya 1.50048 65.996466
H-K2 CDGM 1.50047 66.020774
A88-66 Corning 1.487502 65.807152
N-BK10 Schott 1.49782 66.95
BK10 Schott 1.497821 66.95447
BSL21 Ohara 1.503779 66.814545
Similar Glasses (Sumita)
Glass Manufacturer nd Vd
BK4 Sumita 1.50048 66.0
BK10 Sumita 1.49782 67.0
BK1 Sumita 1.51009 63.4
K-BK7 Sumita 1.51633 64.1
BK7 Sumita 1.51633 64.1
K-PBK40(M) Sumita 1.51497 63.3
P-BK40 Sumita 1.5176 63.5
K-PBK40 Sumita 1.5176 63.5
K11 Sumita 1.50013 61.6
K-PBK50(M) Sumita 1.52025 62.2
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