K-LaKn7 by Sumita

Standard Rare Environmentally Friendly

K-LaKn7 by Sumita is a standard optical glass with a rare melt frequency. It transmits from 0.34 to 2.00 µm with an nd of 1.67 and a Vd of 51.7. It has low thermal expansion (CTE of 6.3×10⁻⁶/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: 0.340–2.000 µm
Optical Properties
Refractive Index (nd) 1.67
Abbe Number (Vd) 51.7
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{2.73574 - 0.0114767\,\lambda^2 + 0.017975\,\lambda^{-2} + 0.000720203\,\lambda^{-4} - 5.1934 \times 10^{-5}\,\lambda^{-6} + 3.59801 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.3
TCE 100/300°C (10-6/K) 8.5
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-2.14 \times 10^{-7} + 2(1.48 \times 10^{-8})\,\Delta T + 3(-1.61 \times 10^{-10})\,\Delta T^2 + \frac{5.55 \times 10^{-7} + 2(4.75 \times 10^{-10})\,\Delta T}{\lambda - 0.191}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.78
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 5
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
H-LAK67 CDGM 1.67 51.738482
LACL4 Hoya 1.669603 51.65903
BBO Generic Birefringent 1.670737 52.593907
LAL56 Ohara 1.677898 50.723364
S-LAL56 Ohara 1.677898 50.722184
LACL9 Hoya 1.6779 50.551353
C58-51 Corning 1.658503 51.012014
SSKN5 Schott 1.65844 50.882921
N-SSK5 Schott 1.65844 50.88
S-BSM25 Ohara 1.658441 50.877554
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LAKN7 Sumita 1.67 51.7
LAKN8 Sumita 1.678 50.7
SSK5 Sumita 1.65844 50.8
LAKN9 Sumita 1.678 53.3
LAKN11 Sumita 1.6583 53.4
K-LaKn11 Sumita 1.6583 53.4
BAFN3 Sumita 1.66422 49.2
K-BaFn3 Sumita 1.66422 49.2
K-VC80(M) Sumita 1.68983 52.9
LAKN10 Sumita 1.692 50.6
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