K-LaK8 by Sumita

Standard Rare Environmentally Friendly

K-LaK8 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 1.713 and a Vd of 53.9. It has low thermal expansion (CTE of 4.9×10⁻⁶/K) and average 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) 1.713
Abbe Number (Vd) 53.9
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{2.87971 - 0.0150095\,\lambda^2 + 0.0193378\,\lambda^{-2} + 0.0004838\,\lambda^{-4} - 1.13679 \times 10^{-5}\,\lambda^{-6} + 7.04843 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 4.9
TCE 100/300°C (10-6/K) 7.5
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[9.91 \times 10^{-7} + 2(1.3 \times 10^{-8})\,\Delta T + 3(-2.26 \times 10^{-10})\,\Delta T^2 + \frac{5.21 \times 10^{-7} + 2(4.99 \times 10^{-10})\,\Delta T}{\lambda - 0.162}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.79
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 4
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
S-LAL8 Ohara 1.712995 53.867058
LAC8 Hoya 1.713 53.94
M-LAC8 Hoya 1.713 53.94
LAL8 Ohara 1.712995 53.845848
D13-54 Corning 1.713 53.843096
MP-LAC8-30 Hoya 1.7133 53.95
H-LAK7A CDGM 1.713 53.832974
LAK8 Schott 1.713003 53.831633
N-LAK8 Schott 1.713 53.83
LAL60 Ohara 1.725999 53.565698
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LAK8 Sumita 1.713 53.9
K-LaK18 Sumita 1.72916 54.7
LAK18 Sumita 1.72916 54.7
LAK13 Sumita 1.6935 53.4
K-VC80 Sumita 1.69384 53.1
LAK14 Sumita 1.6968 55.6
K-LaK14 Sumita 1.6968 55.6
LAK9 Sumita 1.691 54.8
K-LaK9 Sumita 1.691 54.8
K-VC80(M) Sumita 1.68983 52.9
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