FDS20-W by Hoya

Preferred Very Common Environmentally Dangerous

FDS20-W by Hoya is a preferred optical glass with a very common melt frequency. It transmits from 0.39 to 2.50 µm with an nd of 1.86966 and a Vd of 20.02. It has medium thermal expansion (CTE of 7.0×10⁻⁶/K), excellent chemical resistance, and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.36501–1.5296 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.36501–1.5296 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.390–2.500 µm
Optical Properties
Refractive Index (nd) 1.86966
Abbe Number (Vd) 20.02
Dispersion Formula Schott
Wavelength Range 0.36501 — 1.5296 µm
$$n(\lambda) = \sqrt{3.31147 - 0.0194024\,\lambda^2 + 0.0516218\,\lambda^{-2} + 0.0058556\,\lambda^{-4} - 0.000532873\,\lambda^{-6} + 7.31978 \times 10^{-5}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 7.0
TCE 100/300°C (10-6/K) 9.0
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-5.56 \times 10^{-6} + 2(1.23 \times 10^{-8})\,\Delta T + 3(-5.99 \times 10^{-11})\,\Delta T^2 + \frac{1.06 \times 10^{-6} + 2(1.34 \times 10^{-9})\,\Delta T}{\lambda - 0.321}\right] \Delta T = T - T_0, \quad T_0 = 23\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.37
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance 1
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance —
Notes

Recommended glass type

Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
S-NPH5 Ohara 1.858955 22.728736
S-NPH4 Ohara 1.89286 20.36181
K-PSFn190(M) Sumita 1.89816 21.7
K-PSFn1(M) Sumita 1.89945 21.3
SFL57 Schott 1.84666 23.62
PBH55 Ohara 1.84986 24.054274
L-TIH53 Ohara 1.84666 23.773536
S-TIH53 Ohara 1.84666 23.77794
S-TIH53W Ohara 1.84666 23.77794
SF57HHT Schott 1.84666 23.779912
Similar Glasses (Hoya)
Glass Manufacturer nd Vd Compare
FDS90 Hoya 1.84666 23.78
FDS90-SG Hoya 1.84666 23.78
FDS9 Hoya 1.846658 23.826345
FDS90-SGP Hoya 1.84666 23.84
NBFD25 Hoya 1.85451 25.15
M-FDS1 Hoya 1.92286 20.88
E-FDS1-W Hoya 1.92286 20.88
E-FDS1 Hoya 1.92286 20.88
MP-FDS1 Hoya 1.92286 20.88
FDS1 Hoya 1.922859 20.883457
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