LAK12 by Sumita

Obsolete Very Rare Environmentally Dangerous
Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.27–2.0 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.27–2.0 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.310–2.000 µm
Optical Properties
Refractive Index (nd) 1.6779
Abbe Number (Vd) 55.5
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.76242 - 0.0107204\,\lambda^2 + 0.0192796\,\lambda^{-2} - 3.73772 \times 10^{-5}\,\lambda^{-4} + 5.44391 \times 10^{-5}\,\lambda^{-6} - 2.80359 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K)
TCE 100/300°C (10-6/K) 8.1
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.98
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
H-LAK5A CDGM 1.6779 55.51497
LAC12 Hoya 1.6779 55.52
C78-56 Corning 1.678004 55.519168
S-LAL12Q Ohara 1.6779 55.346888
S-LAL12 Ohara 1.6779 55.341195
LAL12 Ohara 1.6779 55.337587
N-LAK12 Schott 1.6779 55.2
LAKN12 Schott 1.6779 55.199566
LAKL12 Schott 1.6779 54.92
D-LAK5 CDGM 1.6779 54.889665
Similar Glasses (Sumita)
Glass Manufacturer nd Vd
K-LaK12 Sumita 1.6779 55.5
K-VC78 Sumita 1.66955 55.4
VC78 Sumita 1.6691 55.4
K-LaFK55(M) Sumita 1.68875 55.8
K-VC78(M) Sumita 1.66624 55.1
K-LaK9 Sumita 1.691 54.8
LAK9 Sumita 1.691 54.8
LAKN4 Sumita 1.671 57.2
K-LaKn4 Sumita 1.671 57.2
LAKN9 Sumita 1.678 53.3
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