K-LaFK50T by Sumita

Standard Medium Precision Molding Environmentally Friendly

K-LaFK50T by Sumita is a standard optical glass with a medium melt frequency. It transmits from 0.29 to 2.00 µm with an nd of 1.766 and a Vd of 49.8. It has low thermal expansion (CTE of 6.3×10⁻⁶/K), good chemical resistance, and precision molding compatibility.

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: 0.290–2.000 µm
Optical Properties
Refractive Index (nd) 1.766
Abbe Number (Vd) 49.8
Dispersion Formula Schott
Wavelength Range 0.36 — 1.55 µm
$$n(\lambda) = \sqrt{3.04996 - 0.0126203\,\lambda^2 + 0.0237825\,\lambda^{-2} + 0.000475586\,\lambda^{-4} + 1.36684 \times 10^{-5}\,\lambda^{-6} - 8.94843 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.3
TCE 100/300°C (10-6/K) 8.1
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.67 \times 10^{-6} + 2(1.57 \times 10^{-8})\,\Delta T + 3(-3.04 \times 10^{-10})\,\Delta T^2 + \frac{6.28 \times 10^{-7} + 2(3.17 \times 10^{-10})\,\Delta T}{\lambda - 0.192}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.75
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 3
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
D-LAF050 CDGM 1.76842 49.28216
D-LAF050-25 CDGM 1.76709 49.197491
M-TAF101 Hoya 1.76802 49.24
MP-TAF101-100 Hoya 1.76902 49.29
MC-TAF101-100 Hoya 1.76902 49.29
MC-TAF115 Hoya 1.77047 49.46
L-LAH91 Ohara 1.7645 49.096913
TAF1 Hoya 1.7725 49.63
N-LAF34 Schott 1.7725 49.62
LAH66 Ohara 1.772499 49.60134
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
K-LaFK50(M) Sumita 1.76831 49.7
K-LaFK50L Sumita 1.7682 50.0
K-LaFK50T(M) Sumita 1.76209 49.6
K-LaFK50 Sumita 1.772 50.0
LASFN7 Sumita 1.7725 49.6
K-LaSFn7 Sumita 1.7725 49.6
LASKN3 Sumita 1.774 50.5
LAFN8 Sumita 1.756 47.6
K-LaSKn1 Sumita 1.755 52.4
LASKN1 Sumita 1.755 52.4
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