FEL4 by Hoya

Obsolete Unknown Environmentally Dangerous
Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.334–2.325 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.334–2.325 µm
Abbe Number Calculator
Transmission vs Wavelength

No transmission data available.

Optical Properties
Refractive Index (nd) 1.561379
Abbe Number (Vd) 45.226718
Dispersion Formula Schott
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{2.38872 - 0.00820679\,\lambda^2 + 0.0169727\,\lambda^{-2} + 0.000283854\,\lambda^{-4} + 1.82034 \times 10^{-5}\,\lambda^{-6} + 3.88924 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K)
TCE 100/300°C (10-6/K)
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$
Physical Properties
Density (g/cm³)
Relative Cost
Mechanical Properties
Young's Modulus (GPa)
Poisson's Ratio
Knoop Hardness (kgf/mm²)
Chemical Resistance
Climatic Resistance
Stain Resistance
Acid Resistance
Alkali Resistance
Phosphate Resistance
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd
LLF4 Sumita 1.56138 45.3
LF8 Schott 1.564435 43.75028
IRG7 Generic IR 1.564424 43.736647
LLF7 Schott 1.548831 45.40834
LLF7 Sumita 1.54869 45.4
PBL7 Ohara 1.548689 45.555746
PBL1Y Ohara 1.548141 45.733282
B48-46 Corning 1.548098 45.718533
LLF1 Schott 1.54814 45.75
PBL1 Ohara 1.548141 45.781144
Similar Glasses (Hoya)
Glass Manufacturer nd Vd
FEL7 Hoya 1.54883 45.439785
FEL3 Hoya 1.560125 47.090971
E-FEL1 Hoya 1.54814 45.82
FEL1 Hoya 1.548136 45.822169
FL6 Hoya 1.567324 42.843119
E-FL6 Hoya 1.56732 42.84
FL1 Hoya 1.573091 42.586108
BAF3 Hoya 1.58267 46.462286
FEL2 Hoya 1.540718 47.198247
E-FEL2 Hoya 1.54072 47.2
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