K-SFLD6 by Sumita

Standard Rare Environmentally Friendly

K-SFLD6 by Sumita is a standard optical glass with a rare melt frequency. It transmits from 0.37 to 2.00 µm with an nd of 1.80518 and a Vd of 25.4. It has medium thermal expansion (CTE of 9.3×10⁻⁶/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: 0.370–2.000 µm
Optical Properties
Refractive Index (nd) 1.80518
Abbe Number (Vd) 25.4
Dispersion Formula Schott
Wavelength Range 0.4 — 1.55 µm
$$n(\lambda) = \sqrt{3.1176 - 0.0121082\,\lambda^2 + 0.0446897\,\lambda^{-2} + 0.00165748\,\lambda^{-4} + 4.19844 \times 10^{-5}\,\lambda^{-6} + 1.29135 \times 10^{-5}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 9.3
TCE 100/300°C (10-6/K) 10.7
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-6.59 \times 10^{-6} + 2(1.77 \times 10^{-8})\,\Delta T + 3(-2.13 \times 10^{-10})\,\Delta T^2 + \frac{1.11 \times 10^{-6} + 2(8.72 \times 10^{-10})\,\Delta T}{\lambda - 0.277}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.4
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
SFL6 Schott 1.80518 25.39
S-TIH6 Ohara 1.805181 25.425363
SF6HT Schott 1.80518 25.43
SF6 Schott 1.80518 25.43
TIH6 Ohara 1.805181 25.432057
PBH6 Ohara 1.805177 25.435012
PBH6W Ohara 1.805177 25.435012
N-SF6HT Schott 1.80518 25.36
N-SF6HTultra Schott 1.80518 25.36
N-SF6 Schott 1.80518 25.36
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
SFLD6 Sumita 1.80518 25.4
SF6W Sumita 1.80518 25.5
SF6 Sumita 1.80518 25.5
K-CD180 Sumita 1.80645 24.4
SFLD60 Sumita 1.80645 24.4
K-CD180(M) Sumita 1.79912 24.7
SFLD66 Sumita 1.79925 24.6
K-SFLD66 Sumita 1.79925 24.6
SFLD20 Sumita 1.81786 23.7
SF11W Sumita 1.78472 25.7
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