N-BALF4 by Schott

Preferred Unknown Environmentally Friendly

N-BALF4 by Schott is a preferred optical glass. It transmits from 0.35 to 2.50 µm with an nd of 1.57956 and a Vd of 53.87. It has medium thermal expansion (CTE of 6.52×10⁻⁶/K), excellent chemical resistance, and low relative cost.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.35–2.5 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.35–2.5 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.350–2.500 µm
Optical Properties
Refractive Index (nd) 1.57956
Abbe Number (Vd) 53.87
Dispersion Formula Sellmeier
Wavelength Range 0.35 — 2.5 µm
$$n(\lambda) = \sqrt{1 + \frac{1.31004\,\lambda^2}{\lambda^2 - 0.00796596} + \frac{0.142038\,\lambda^2}{\lambda^2 - 0.0330672} + \frac{0.964929\,\lambda^2}{\lambda^2 - 109.197}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.52
TCE 100/300°C (10-6/K) 7.41
Thermal Conductivity (W/mK) 0.85
Heat Capacity (J/gK) 0.69
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[5.33 \times 10^{-6} + 2(1.47 \times 10^{-8})\,\Delta T + 3(-1.58 \times 10^{-11})\,\Delta T^2 + \frac{5.75 \times 10^{-7} + 2(6.58 \times 10^{-10})\,\Delta T}{\lambda - 0.195}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.111
Relative Cost 2.1
Mechanical Properties
Young's Modulus (GPa) 77.0
Poisson's Ratio 0.25
Knoop Hardness (kgf/mm²) 540.0
Chemical Resistance
Climatic Resistance 1
Stain Resistance 0
Acid Resistance 1
Alkali Resistance 1
Phosphate Resistance 1
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
H-BAF3 CDGM 1.57957 53.711637
BAFL4 Hoya 1.579572 53.705963
BALF3 Sumita 1.57135 53.0
BAFL3 Hoya 1.571348 52.982526
BAL3 Ohara 1.571351 52.968158
S-BAL3 Ohara 1.571351 52.952106
BALF6 Sumita 1.58904 53.2
BAFL6 Hoya 1.589036 52.935166
ADF1 Hoya 1.564997 52.958253
BAK4 Sumita 1.56883 56.0
Similar Glasses (Schott)
Glass Manufacturer nd Vd Compare
BALF4 Schott 1.579569 53.708241
N-BAK4HT Schott 1.56883 55.98
N-BAK4 Schott 1.56883 55.98
BAK4 Schott 1.56883 56.130661
BALF50 Schott 1.588931 51.371228
N-KZFS2 Schott 1.55836 54.01
KZFSN2 Schott 1.558361 54.157173
SSK51 Schott 1.603607 53.631714
BAK1 Schott 1.5725 57.54931
N-BAK1 Schott 1.5725 57.55
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