K-LaSFn4 by Sumita

Standard Rare Environmentally Friendly

K-LaSFn4 by Sumita is a standard optical glass with a rare melt frequency. It transmits from 0.31 to 2.00 µm with an nd of 1.785 and a Vd of 43.7. It has medium thermal expansion (CTE of 6.9×10⁻⁶/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: 0.310–2.000 µm
Optical Properties
Refractive Index (nd) 1.785
Abbe Number (Vd) 43.7
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{3.105 - 0.0133425\,\lambda^2 + 0.0275065\,\lambda^{-2} + 0.000754516\,\lambda^{-4} - 1.65657 \times 10^{-5}\,\lambda^{-6} + 2.78048 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.9
TCE 100/300°C (10-6/K) 8.3
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-6.24 \times 10^{-7} + 2(1.69 \times 10^{-8})\,\Delta T + 3(-1.42 \times 10^{-10})\,\Delta T^2 + \frac{6.93 \times 10^{-7} + 2(1.19 \times 10^{-9})\,\Delta T}{\lambda - 0.208}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.12
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
LAFN10 Schott 1.784432 43.950523
NBFD11 Hoya 1.7859 43.94
N-LAF33 Schott 1.78582 44.05
LAH51 Ohara 1.785896 44.186159
H-LAF52 CDGM 1.7859 44.187159
S-LAH51 Ohara 1.785896 44.202637
NBFD1 Hoya 1.789004 42.757634
D96-43 Corning 1.796195 43.217783
LAH67 Ohara 1.794997 45.293967
S-LAH67 Ohara 1.794997 45.293967
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LASFN4 Sumita 1.785 43.7
K-VC100(M) Sumita 1.79916 43.5
LASFN19 Sumita 1.795 45.2
K-VC179(M) Sumita 1.79441 41.9
K-LaSFn3 Sumita 1.7995 42.3
LASFN3 Sumita 1.7995 42.3
K-VC100 Sumita 1.804 43.6
K-VC179 Sumita 1.7989 41.8
K-LaSFn16 Sumita 1.7883 47.4
LASFN16 Sumita 1.7883 47.4
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