K-SK18 by Sumita

Standard Rare Environmentally Friendly
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: 0.330–2.000 µm
Optical Properties
Refractive Index (nd) 1.63854
Abbe Number (Vd) 55.5
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{2.63832 - 0.010807\,\lambda^2 + 0.0161534\,\lambda^{-2} + 0.00046674\,\lambda^{-4} - 2.54146 \times 10^{-5}\,\lambda^{-6} + 1.97032 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.8
TCE 100/300°C (10-6/K) 8.1
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.85 \times 10^{-6} + 2(1.9 \times 10^{-8})\,\Delta T + 3(-1.3 \times 10^{-10})\,\Delta T^2 + \frac{4.59 \times 10^{-7} + 2(9.89 \times 10^{-10})\,\Delta T}{\lambda - 0.204}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.69
Relative Cost
Mechanical Properties
Young's Modulus (GPa)
Poisson's Ratio
Knoop Hardness (kgf/mm²)
Chemical Resistance
Climatic Resistance 3
Stain Resistance
Acid Resistance 5
Alkali Resistance
Phosphate Resistance
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd
C39-56 Corning 1.638505 55.504447
BACD18 Hoya 1.63854 55.45
H-ZK11 CDGM 1.63854 55.446553
N-SK18 Schott 1.63854 55.423596
SK18A Schott 1.63854 55.423596
BSM18 Ohara 1.638539 55.384768
S-BSM18 Ohara 1.638539 55.380028
M-PCD55AR Hoya 1.63858 55.18
MP-PCD55AR Hoya 1.63858 55.18
LACL1 Hoya 1.640851 56.835319
Similar Glasses (Sumita)
Glass Manufacturer nd Vd
SK18RH Sumita 1.63854 55.5
SK18 Sumita 1.63854 55.5
K-SK18RH Sumita 1.63854 55.5
LAKN13 Sumita 1.641 56.8
K-LaKn5 Sumita 1.65 55.8
LAKN5 Sumita 1.65 55.8
SK10 Sumita 1.6228 56.9
LAK6 Sumita 1.6425 58.1
K-LaK6 Sumita 1.6425 58.1
SSKN1 Sumita 1.6485 53.0
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