N-LASF31A by Schott

Preferred Unknown Environmentally Friendly

N-LASF31A by Schott is a preferred optical glass. It transmits from 0.33 to 2.50 µm with an nd of 1.883 and a Vd of 40.76. It has medium thermal expansion (CTE of 6.74×10⁻⁶/K), excellent chemical resistance, and high relative cost.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.334–2.5 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.334–2.5 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.334–2.500 µm
Optical Properties
Refractive Index (nd) 1.883
Abbe Number (Vd) 40.76
Dispersion Formula Sellmeier
Wavelength Range 0.334 — 2.5 µm
$$n(\lambda) = \sqrt{1 + \frac{1.96485\,\lambda^2}{\lambda^2 - 0.0098206} + \frac{0.475231\,\lambda^2}{\lambda^2 - 0.0344713} + \frac{1.4836\,\lambda^2}{\lambda^2 - 110.74}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.74
TCE 100/300°C (10-6/K) 7.72
Thermal Conductivity (W/mK) 0.79
Heat Capacity (J/gK) 0.44
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[1.67 \times 10^{-6} + 2(8.9 \times 10^{-9})\,\Delta T + 3(-8.73 \times 10^{-12})\,\Delta T^2 + \frac{7.47 \times 10^{-7} + 2(7.46 \times 10^{-10})\,\Delta T}{\lambda - 0.207}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 5.51
Relative Cost 14.4
Mechanical Properties
Young's Modulus (GPa) 125.51
Poisson's Ratio 0.3
Knoop Hardness (kgf/mm²) 650.0
Chemical Resistance
Climatic Resistance 1
Stain Resistance 0
Acid Resistance 2
Alkali Resistance 1
Phosphate Resistance 1
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
S-LAH58 Ohara 1.882997 40.765107
LAH58 Ohara 1.882997 40.778667
K-LaSFn17 Sumita 1.883 40.8
H-ZLAF68B CDGM 1.883004 40.806875
TAFD30 Hoya 1.883 40.81
H-ZLAF68C CDGM 1.883 40.847465
LASFN17 Sumita 1.883 40.9
H-ZLAF73 CDGM 1.881 40.161331
TAFD33 Hoya 1.881 40.14
H-ZLAF68NB CDGM 1.883 39.235474
Similar Glasses (Schott)
Glass Manufacturer nd Vd Compare
LASFN31 Schott 1.880669 41.009774
N-LASF31 Schott 1.88067 41.01
LASFN15 Schott 1.878001 38.072485
N-LASF41 Schott 1.83501 43.13
N-LASF40 Schott 1.83404 37.3
LASF14A Schott 1.822226 37.454652
LASF18A Schott 1.913482 32.364492
N-LASF46 Schott 1.90138 31.64
N-LASF9 Schott 1.85025 32.17
N-LASF9HT Schott 1.85025 32.17
Compare Glasses
    Compare Selected