K-LaSFn8 by Sumita

Standard Rare Environmentally Friendly

K-LaSFn8 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 1.835 and a Vd of 42.7. It has low thermal expansion (CTE of 6.0×10⁻⁶/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) 1.835
Abbe Number (Vd) 42.7
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{3.27673 - 0.0151156\,\lambda^2 + 0.0307534\,\lambda^{-2} + 0.000783506\,\lambda^{-4} - 3.45945 \times 10^{-6}\,\lambda^{-6} + 2.05426 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.0
TCE 100/300°C (10-6/K) 7.4
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.92 \times 10^{-6} + 2(1.65 \times 10^{-8})\,\Delta T + 3(-2.32 \times 10^{-10})\,\Delta T^2 + \frac{6.04 \times 10^{-7} + 2(6.91 \times 10^{-10})\,\Delta T}{\lambda - 0.225}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.9
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 2
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
H-ZLAF55C CDGM 1.83481 42.711575
S-LAH55 Ohara 1.834807 42.713673
TAFD5G Hoya 1.83481 42.72
TAFD5F Hoya 1.83481 42.72
LAH55 Ohara 1.834807 42.72372
H-ZLAF55D CDGM 1.83481 42.725177
S-LAH55V Ohara 1.834807 42.725324
S-LAH55VS Ohara 1.834809 42.74368
TAFD5 Hoya 1.835 42.984244
N-LASF41 Schott 1.83501 43.13
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LASFN8 Sumita 1.835 42.7
K-LaSFn8W Sumita 1.8349 42.7
K-VC99(M) Sumita 1.84604 41.5
K-VC99 Sumita 1.8506 41.6
K-VC185(M) Sumita 1.84909 40.5
K-LaSFn10 Sumita 1.8155 44.4
LASFN10 Sumita 1.8155 44.4
K-VC185 Sumita 1.85375 40.6
K-VC181 Sumita 1.81055 41.1
K-VC89 Sumita 1.81 41.0
Compare Glasses
    Compare Selected