NBFD25 by Hoya

Preferred Very Common Environmentally Dangerous

NBFD25 by Hoya is a preferred optical glass with a very common melt frequency. It transmits from 0.36 to 2.50 µm with an nd of 1.85451 and a Vd of 25.15. It has medium thermal expansion (CTE of 8.1×10⁻⁶/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: 0.360–2.500 µm
Optical Properties
Refractive Index (nd) 1.85451
Abbe Number (Vd) 25.15
Dispersion Formula Schott
Wavelength Range 0.36501 — 1.5296 µm
$$n(\lambda) = \sqrt{3.28794 - 0.0158564\,\lambda^2 + 0.0456388\,\lambda^{-2} + 0.00330277\,\lambda^{-4} - 0.000216907\,\lambda^{-6} + 2.96259 \times 10^{-5}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 8.1
TCE 100/300°C (10-6/K) 10.5
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.95 \times 10^{-6} + 2(7.85 \times 10^{-9})\,\Delta T + 3(-1.91 \times 10^{-11})\,\Delta T^2 + \frac{8.43 \times 10^{-7} + 2(7.47 \times 10^{-10})\,\Delta T}{\lambda - 0.3}\right] \Delta T = T - T_0, \quad T_0 = 23\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.48
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-NBH56 Ohara 1.854779 24.79898
PBH55 Ohara 1.84986 24.054274
K-PSFn4 Sumita 1.844 24.8
SFN3 Sumita 1.84666 23.9
SFLDN3 Sumita 1.84666 23.9
PBH53W Ohara 1.846658 23.885544
PBH53 Ohara 1.846658 23.885544
S-NPH53 Ohara 1.84666 23.88395
SF57HTultra Schott 1.84666 23.83
SF57 Schott 1.84666 23.83
Similar Glasses (Hoya)
Glass Manufacturer nd Vd Compare
FDS90-SGP Hoya 1.84666 23.84
FDS9 Hoya 1.846658 23.826345
FDS90-SG Hoya 1.84666 23.78
FDS90 Hoya 1.84666 23.78
NBFD26 Hoya 1.83401 25.97
MC-FDS910-50 Hoya 1.82165 24.04
MP-FDS910-50 Hoya 1.82165 24.04
M-FDS910 Hoya 1.82115 24.06
NBFD30 Hoya 1.85883 30.0
FDS20-W Hoya 1.86966 20.02
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