K-LaSFn23 by Sumita

Standard Rare Environmentally Friendly

K-LaSFn23 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 1.911 and a Vd of 35.2. It has medium thermal expansion (CTE of 6.9×10⁻⁶/K) and excellent 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) 1.911
Abbe Number (Vd) 35.2
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{3.52744 - 0.0146407\,\lambda^2 + 0.0403938\,\lambda^{-2} + 0.00154951\,\lambda^{-4} - 4.56672 \times 10^{-5}\,\lambda^{-6} + 9.09713 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.9
TCE 100/300°C (10-6/K) 8.8
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.83 \times 10^{-8} + 2(1.49 \times 10^{-8})\,\Delta T + 3(-2.69 \times 10^{-10})\,\Delta T^2 + \frac{8.28 \times 10^{-7} + 2(7.87 \times 10^{-10})\,\Delta T}{\lambda - 0.248}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.9
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
TAFD35 Hoya 1.91082 35.25
TAFD35L Hoya 1.91082 35.25
H-ZLAF4LA CDGM 1.91082 35.25034
H-ZLAF4LB CDGM 1.91082 35.282389
S-LAH93 Ohara 1.90525 35.036826
CAWO4 Generic Birefringent 1.920414 34.953592
TAFD31 Hoya 1.922501 35.946005
H-ZLAF78B CDGM 1.90069 37.050531
TAFD37 Hoya 1.90043 37.37
TAFD37A Hoya 1.90043 37.37
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
LASFN22 Sumita 1.898 34.0
K-LaSFn22 Sumita 1.898 34.0
K-VC91 Sumita 1.8866 35.0
K-VC91(M) Sumita 1.88175 34.9
K-LaSFn17 Sumita 1.883 40.8
LASFN17 Sumita 1.883 40.9
K-GIR79 Sumita 1.8592 33.0
LASFN21 Sumita 1.85 32.4
K-LaSFn21 Sumita 1.85 32.4
K-VC90 Sumita 1.8528 39.0
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