K-LaSFn2 by Sumita

Standard Medium Environmentally Friendly

K-LaSFn2 by Sumita is a standard optical glass with a medium melt frequency. It transmits from 0.32 to 2.00 µm with an nd of 1.805 and a Vd of 39.6. It has low thermal expansion (CTE of 5.6×10⁻⁶/K) and good chemical resistance.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.36–1.55 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.36–1.55 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.320–2.000 µm
Optical Properties
Refractive Index (nd) 1.805
Abbe Number (Vd) 39.6
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{3.16665 - 0.014823\,\lambda^2 + 0.0303661\,\lambda^{-2} + 0.00109429\,\lambda^{-4} - 4.21086 \times 10^{-5}\,\lambda^{-6} + 5.71868 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 5.6
TCE 100/300°C (10-6/K) 7.0
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[5.26 \times 10^{-6} + 2(1.83 \times 10^{-8})\,\Delta T + 3(-3.28 \times 10^{-10})\,\Delta T^2 + \frac{7.62 \times 10^{-7} + 2(8.92 \times 10^{-10})\,\Delta T}{\lambda - 0.222}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.13
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 Compare
H-ZLAF51 CDGM 1.8045 39.635248
NBFD3 Hoya 1.8045 39.64
S-LAH63 Ohara 1.804398 39.58615
S-LAH63Q Ohara 1.8044 39.580489
LAH63 Ohara 1.804398 39.581254
L-LAH81 Ohara 1.8061 40.400738
P-LASF50 Schott 1.8086 40.46
N-LASF43 Schott 1.8061 40.61
L-LAH84 Ohara 1.80835 40.548503
LASF3 Schott 1.808009 40.610164
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LASFN2 Sumita 1.805 39.6
LASFN1 Sumita 1.806 40.7
K-LaSFn1 Sumita 1.8061 40.7
K-VC89(M) Sumita 1.8059 40.9
K-VC181(M) Sumita 1.80614 41.1
K-VC89 Sumita 1.81 41.0
K-VC181 Sumita 1.81055 41.1
K-VC179 Sumita 1.7989 41.8
K-VC179(M) Sumita 1.79441 41.9
K-LaSFn3 Sumita 1.7995 42.3
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