K-LaSFn7 by Sumita

Standard Rare Environmentally Friendly

K-LaSFn7 by Sumita is a standard optical glass with a rare melt frequency. It transmits from 0.30 to 2.00 µm with an nd of 1.7725 and a Vd of 49.6. It has low thermal expansion (CTE of 5.7×10⁻⁶/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: 0.300–2.000 µm
Optical Properties
Refractive Index (nd) 1.7725
Abbe Number (Vd) 49.6
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{3.07288 - 0.0148153\,\lambda^2 + 0.0240641\,\lambda^{-2} + 0.000499615\,\lambda^{-4} + 1.28528 \times 10^{-6}\,\lambda^{-6} + 5.22621 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 5.7
TCE 100/300°C (10-6/K) 7.2
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.19 \times 10^{-6} + 2(1.73 \times 10^{-8})\,\Delta T + 3(-1.56 \times 10^{-10})\,\Delta T^2 + \frac{5.97 \times 10^{-7} + 2(3.56 \times 10^{-10})\,\Delta T}{\lambda - 0.161}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.44
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-LAF50B CDGM 1.7725 49.598996
LAH66 Ohara 1.772499 49.60134
S-LAH66 Ohara 1.772499 49.598371
N-LAF34 Schott 1.7725 49.62
TAF1 Hoya 1.7725 49.63
LAFN28 Schott 1.773142 49.568242
D-LAF50-25 CDGM 1.77288 49.519338
MC-TAF105 Hoya 1.7725 49.5
M-TAF105 Hoya 1.7725 49.5
MP-TAF105 Hoya 1.7725 49.5
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LASFN7 Sumita 1.7725 49.6
K-LaFK50 Sumita 1.772 50.0
K-LaFK50(M) Sumita 1.76831 49.7
K-LaFK50L Sumita 1.7682 50.0
K-LaFK50T Sumita 1.766 49.8
LASKN3 Sumita 1.774 50.5
K-LaFK50T(M) Sumita 1.76209 49.6
LAFN8 Sumita 1.756 47.6
K-LaSFn16 Sumita 1.7883 47.4
LASFN16 Sumita 1.7883 47.4
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