BSM21 by Ohara

Obsolete Unknown Environmentally Dangerous
Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.365–0.9 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.365–0.9 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.370–0.700 µm
Optical Properties
Refractive Index (nd) 1.617196
Abbe Number (Vd) 54.040511
Dispersion Formula Schott
Wavelength Range 0.365 — 0.9 µm
$$n(\lambda) = \sqrt{2.56787 - 0.00865733\,\lambda^2 + 0.0165914\,\lambda^{-2} + 0.000286555\,\lambda^{-4} - 3.48868 \times 10^{-6}\,\lambda^{-6} + 8.92755 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.3
TCE 100/300°C (10-6/K) 7.3
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.3634 \times 10^{-6} + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.63
Relative Cost
Mechanical Properties
Young's Modulus (GPa)
Poisson's Ratio
Knoop Hardness (kgf/mm²)
Chemical Resistance
Climatic Resistance
Stain Resistance
Acid Resistance
Alkali Resistance
Phosphate Resistance
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd
SSK1 Sumita 1.6172 54.0
K-SSK1 Sumita 1.6172 54.0
BACED1 Hoya 1.617203 53.945664
H-ZK20 CDGM 1.6172 53.913743
SSK1 Schott 1.617201 53.912403
N-SSK2 Schott 1.62229 53.27
SSK4 Sumita 1.61765 55.1
K-SSK4 Sumita 1.61765 55.1
C17-55 Corning 1.617605 55.123455
SSK4A Schott 1.61765 55.141867
Similar Glasses (Ohara)
Glass Manufacturer nd Vd
S-BSM21 Ohara 1.617195 54.062144
BSM24 Ohara 1.617646 55.049782
BSM9 Ohara 1.614047 54.971106
S-BSM9 Ohara 1.614047 54.990097
BSM22 Ohara 1.622296 53.186644
S-BSM22 Ohara 1.622296 53.169067
BSM6 Ohara 1.613749 56.365919
BSM23 Ohara 1.614839 51.172377
BSM2 Ohara 1.607379 56.815789
S-BSM2 Ohara 1.607379 56.816076
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