S-BSM21 by Ohara

Obsolete Unknown Environmentally Friendly

S-BSM21 by Ohara is an obsolete optical glass. It transmits from 0.34 to 0.90 µm with an nd of 1.617195 and a Vd of 54.062144. It has low thermal expansion (CTE of 6.5×10⁻⁶/K) and good chemical resistance.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.3–2.4 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.3–2.4 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.340–0.900 µm
Optical Properties
Refractive Index (nd) 1.617195
Abbe Number (Vd) 54.062144
Dispersion Formula Sellmeier
Wavelength Range 0.3 — 2.4 µm
$$n(\lambda) = \sqrt{1 + \frac{1.47868\,\lambda^2}{\lambda^2 - 0.00869706} + \frac{0.0899501\,\lambda^2}{\lambda^2 - 0.0399354} + \frac{1.03057\,\lambda^2}{\lambda^2 - 108.551}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.5
TCE 100/300°C (10-6/K) 7.6
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.49
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 2
Stain Resistance —
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance 1
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
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
K-SSK4 Sumita 1.61765 55.1
SSK4 Sumita 1.61765 55.1
N-SSK2 Schott 1.62229 53.27
C17-55 Corning 1.617605 55.123455
SSK4A Schott 1.61765 55.141867
Similar Glasses (Ohara)
Glass Manufacturer nd Vd Compare
BSM21 Ohara 1.617196 54.040511
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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