K-LaSFn21 by Sumita

Standard Rare Environmentally Friendly
Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.4–1.55 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.4–1.55 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.350–2.000 µm
Optical Properties
Refractive Index (nd) 1.85
Abbe Number (Vd) 32.4
Dispersion Formula Schott
Wavelength Range 0.4 — 1.55 µm
$$n(\lambda) = \sqrt{3.30403 - 0.0160197\,\lambda^2 + 0.037646\,\lambda^{-2} + 0.00215325\,\lambda^{-4} - 0.000204981\,\lambda^{-6} + 2.76232 \times 10^{-5}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.0
TCE 100/300°C (10-6/K) 7.6
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[3.35 \times 10^{-6} + 2(1.38 \times 10^{-8})\,\Delta T + 3(-2.07 \times 10^{-11})\,\Delta T^2 + \frac{8.23 \times 10^{-7} + 2(1.31 \times 10^{-9})\,\Delta T}{\lambda - 0.268}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.99
Relative Cost
Mechanical Properties
Young's Modulus (GPa)
Poisson's Ratio
Knoop Hardness (kgf/mm²)
Chemical Resistance
Climatic Resistance 1
Stain Resistance
Acid Resistance 3
Alkali Resistance
Phosphate Resistance
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd
H-ZLAF71 CDGM 1.85026 32.297288
LAH71 Ohara 1.850259 32.28594
S-LAH71 Ohara 1.850259 32.27012
H-ZLAF71AGT CDGM 1.85026 32.216801
TAFD9 Hoya 1.850299 32.181026
N-LASF9 Schott 1.85025 32.17
LASFN9 Schott 1.85025 32.17
N-LASF9HT Schott 1.85025 32.17
IRG3 Generic IR 1.844836 32.330322
H-ZLAF76 CDGM 1.85013 30.055517
Similar Glasses (Sumita)
Glass Manufacturer nd Vd
LASFN21 Sumita 1.85 32.4
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K-LaSFn14 Sumita 1.834 37.3
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K-VC91 Sumita 1.8866 35.0
K-VC90(M) Sumita 1.84859 38.9
K-VC90 Sumita 1.8528 39.0
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