TAFD21 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) 1.9326
Abbe Number (Vd) 27.921009
Dispersion Formula Schott
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{3.58656 - 0.021123\,\lambda^2 + 0.0426816\,\lambda^{-2} + 0.0046837\,\lambda^{-4} - 0.000412009\,\lambda^{-6} + 3.91344 \times 10^{-5}\,\lambda^{-8}}$$
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-E Generic Birefringent 1.913456 28.381356
SRMOO4 Generic Birefringent 1.908806 29.94765
N-LASF55 Schott 1.9538 30.56
S-LAH88 Ohara 1.916499 31.604148
L-NBH54 Ohara 1.902 25.101413
L-LAH86 Ohara 1.902699 31.00532
LASF18A Schott 1.913482 32.364492
H-ZLAF75A CDGM 1.90366 31.31497
N-LASF46B Schott 1.90366 31.32
N-LASF46A Schott 1.90366 31.32
Similar Glasses (Hoya)
Glass Manufacturer nd Vd
NBFD265 Hoya 1.95203 26.2
MP-TAFD405 Hoya 1.9515 29.83
M-TAFD405 Hoya 1.9515 29.83
FDS24-SW Hoya 1.92119 23.96
FDS24 Hoya 1.92119 23.96
FDS24-W Hoya 1.92119 23.96
NBFD27 Hoya 1.9011 27.06
TAFD20 Hoya 1.90315 29.835563
TAFD25 Hoya 1.90366 31.32
TAFD25L Hoya 1.90366 31.32
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