N-LAK7 by Schott

Preferred Unknown Environmentally Friendly

N-LAK7 by Schott is a preferred optical glass. It transmits from 0.30 to 2.50 µm with an nd of 1.6516 and a Vd of 58.52. It has medium thermal expansion (CTE of 7.1×10⁻⁶/K), below average chemical resistance, and low relative cost.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.3–2.5 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.3–2.5 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.300–2.500 µm
Optical Properties
Refractive Index (nd) 1.6516
Abbe Number (Vd) 58.52
Dispersion Formula Sellmeier
Wavelength Range 0.3 — 2.5 µm
$$n(\lambda) = \sqrt{1 + \frac{1.2368\,\lambda^2}{\lambda^2 - 0.00610106} + \frac{0.445052\,\lambda^2}{\lambda^2 - 0.0201388} + \frac{1.01746\,\lambda^2}{\lambda^2 - 90.638}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 7.1
TCE 100/300°C (10-6/K) 8.2
Thermal Conductivity (W/mK) 0.74
Heat Capacity (J/gK) 0.53
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-3.4 \times 10^{-6} + 2(1.17 \times 10^{-8})\,\Delta T + 3(2.38 \times 10^{-11})\,\Delta T^2 + \frac{4.96 \times 10^{-7} + 2(4.44 \times 10^{-10})\,\Delta T}{\lambda - 0.107}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.84
Relative Cost 2.0
Mechanical Properties
Young's Modulus (GPa) 90.0
Poisson's Ratio 0.28
Knoop Hardness (kgf/mm²) 600.0
Chemical Resistance
Climatic Resistance 3
Stain Resistance 2
Acid Resistance 53
Alkali Resistance 3
Phosphate Resistance 4
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
LAL7 Ohara 1.651597 58.519433
C52-58 Corning 1.6516 58.511488
S-LAL7Q Ohara 1.6516 58.544459
S-LAL7 Ohara 1.651597 58.550655
H-LAK50A CDGM 1.6516 58.403057
LAC7 Hoya 1.6516 58.4
K-LaK7 Sumita 1.6516 58.3
LAK7 Sumita 1.6516 58.3
BSM36 Ohara 1.642495 58.369399
S-BSM36 Ohara 1.642495 58.369399
Similar Glasses (Schott)
Glass Manufacturer nd Vd Compare
LAKN7 Schott 1.6516 58.517773
LAKN6 Schott 1.642499 57.962061
LAK11 Schott 1.658302 57.261599
LAKL21 Schott 1.64048 59.749915
N-LAK21 Schott 1.64049 60.1
LAK21 Schott 1.640495 60.101885
LAK23 Schott 1.668816 57.38444
LAKN22 Schott 1.65113 55.891754
N-LAK22 Schott 1.65113 55.89
SK18A Schott 1.63854 55.423596
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