K-SFLD8W by Sumita

Standard Rare Environmentally Friendly

K-SFLD8W by Sumita is a standard optical glass with a rare melt frequency. It transmits from 0.35 to 2.00 µm with an nd of 1.6891 and a Vd of 31.2. It has medium thermal expansion (CTE of 7.8×10⁻⁶/K) and excellent chemical resistance.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.4–1.55 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.4–1.55 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.350–2.000 µm
Optical Properties
Refractive Index (nd) 1.6891
Abbe Number (Vd) 31.2
Dispersion Formula Schott
Wavelength Range 0.4 — 1.55 µm
$$n(\lambda) = \sqrt{2.7616 - 0.0116252\,\lambda^2 + 0.0292517\,\lambda^{-2} + 0.00131837\,\lambda^{-4} - 4.40209 \times 10^{-5}\,\lambda^{-6} + 1.04864 \times 10^{-5}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 7.8
TCE 100/300°C (10-6/K) 9.3
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.03 \times 10^{-6} + 2(9.91 \times 10^{-9})\,\Delta T + 3(-1.57 \times 10^{-10})\,\Delta T^2 + \frac{8.38 \times 10^{-7} + 2(2.42 \times 10^{-9})\,\Delta T}{\lambda - 0.279}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 2.94
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
C89-31 Corning 1.689004 31.210861
ZF10 CDGM 1.688934 31.184753
SF8 Schott 1.688932 31.176063
H-ZF10 CDGM 1.68893 31.16057
MP-FD80 Hoya 1.68893 31.16
M-FD80 Hoya 1.68893 31.16
E-FD8 Hoya 1.68893 31.16
MC-FD80 Hoya 1.68893 31.16
FD8 Hoya 1.688931 31.158857
P-SF8 Schott 1.68893 31.25
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
SF8 Sumita 1.68893 31.2
K-SFLD8 Sumita 1.68893 31.1
K-CD300(M) Sumita 1.68558 29.9
K-CD300 Sumita 1.6922 29.6
SF15 Sumita 1.69895 30.0
SF5 Sumita 1.6727 32.2
CD45 Sumita 1.6932 33.7
K-CD45 Sumita 1.6932 33.7
K-CD45(M) Sumita 1.68673 34.1
SF19 Sumita 1.6668 33.1
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