TAFD20 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) 1.90315
Abbe Number (Vd) 29.835563
Dispersion Formula Schott
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{3.48514 - 0.0172006\,\lambda^2 + 0.0408385\,\lambda^{-2} + 0.00349092\,\lambda^{-4} - 0.000280844\,\lambda^{-6} + 2.86509 \times 10^{-5}\,\lambda^{-8}}$$
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
SRMOO4 Generic Birefringent 1.908806 29.94765
L-LAH86 Ohara 1.902699 31.00532
H-ZLAF75A CDGM 1.90366 31.31497
N-LASF46A Schott 1.90366 31.32
N-LASF46B Schott 1.90366 31.32
S-LAH95 Ohara 1.903659 31.343065
H-ZLAF75C CDGM 1.90366 31.357126
IRG2 Generic IR 1.891717 29.896648
H-ZLAF75B CDGM 1.90366 31.418411
LAH78 Ohara 1.901355 31.550244
Similar Glasses (Hoya)
Glass Manufacturer nd Vd
TAFD25 Hoya 1.90366 31.32
TAFD25L Hoya 1.90366 31.32
NBFD27 Hoya 1.9011 27.06
TAFD21 Hoya 1.9326 27.921009
TAFD35 Hoya 1.91082 35.25
TAFD35L Hoya 1.91082 35.25
NBFD30 Hoya 1.85883 30.0
FDS24 Hoya 1.92119 23.96
FDS24-W Hoya 1.92119 23.96
FDS24-SW Hoya 1.92119 23.96
Compare Glasses