LAKL21 by Schott

Obsolete Unknown Environmentally Dangerous

LAKL21 by Schott is an obsolete optical glass. It transmits from 0.33 to 2.33 µm with an nd of 1.64048 and a Vd of 59.749915. It has low thermal expansion (CTE of 6.1×10⁻⁶/K) and dangerous environmental properties.

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
Transmission Calculator
Valid wavelength range: 0.334–2.325 µm
Optical Properties
Refractive Index (nd) 1.64048
Abbe Number (Vd) 59.749915
Dispersion Formula Sellmeier
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{1 + \frac{1.29854\,\lambda^2}{\lambda^2 - 0.00628044} + \frac{0.350522\,\lambda^2}{\lambda^2 - 0.0210843} + \frac{1.1709\,\lambda^2}{\lambda^2 - 85.4205}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.1
TCE 100/300°C (10-6/K) 7.4
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[2.58 \times 10^{-6} + 2(1.19 \times 10^{-8})\,\Delta T + 3(-5.03 \times 10^{-11})\,\Delta T^2 + \frac{2.69 \times 10^{-7} + 2(2.47 \times 10^{-10})\,\Delta T}{\lambda - 0.265}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 2.97
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 —
Notes

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Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
S-BSM81 Ohara 1.639999 60.078127
BSM81 Ohara 1.639999 60.091709
LAKN2 Sumita 1.6405 60.1
K-LaKn2 Sumita 1.6405 60.1
C41-60 Corning 1.640495 60.130957
LACL6 Hoya 1.640003 60.153568
LACL60 Hoya 1.64 60.2
H-LAK4L CDGM 1.64 60.202769
BSM36 Ohara 1.642495 58.369399
S-BSM36 Ohara 1.642495 58.369399
Similar Glasses (Schott)
Glass Manufacturer nd Vd Compare
N-LAK21 Schott 1.64049 60.1
LAK21 Schott 1.640495 60.101885
LAKN6 Schott 1.642499 57.962061
N-LAK7 Schott 1.6516 58.52
LAKN7 Schott 1.6516 58.517773
SK51 Schott 1.6209 60.310926
SK55 Schott 1.620411 60.118763
N-SK16 Schott 1.62041 60.32
SK16 Schott 1.62041 60.323649
SK15 Schott 1.62299 58.059722
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