SK18 by Sumita
Obsolete
Very Rare
Environmentally Dangerous
Refractive Index vs Wavelength
Refractive Index Calculator
dn/dλ vs Wavelength
dn/dλ Calculator
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Optical Properties
| Refractive Index (nd) | 1.63854 |
|---|---|
| Abbe Number (Vd) | 55.5 |
| Dispersion Formula | Schott |
| Wavelength Range | 0.27 — 2.0 µm |
$$n(\lambda) = \sqrt{2.63842 - 0.0108276\,\lambda^2 + 0.0160588\,\lambda^{-2} + 0.000501226\,\lambda^{-4} - 3.06877 \times 10^{-5}\,\lambda^{-6} + 2.25464 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
| TCE -30/70°C (10-6/K) | — |
|---|---|
| TCE 100/300°C (10-6/K) | 8.1 |
| Thermal Conductivity (W/mK) | — |
| Heat Capacity (J/gK) | — |
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right]
\Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
| Density (g/cm³) | 3.69 |
|---|---|
| Relative Cost | — |
Mechanical Properties
| Young's Modulus (GPa) | — |
|---|---|
| Poisson's Ratio | — |
| Knoop Hardness (kgf/mm²) | — |
Chemical Resistance
| Climatic Resistance | 2 |
|---|---|
| Stain Resistance | — |
| Acid Resistance | 5 |
| Alkali Resistance | — |
| Phosphate Resistance | — |
Similar Glasses (Other Manufacturers)
| Glass | Manufacturer | nd | Vd | |
|---|---|---|---|---|
| C39-56 | Corning | 1.638505 | 55.504447 | |
| BACD18 | Hoya | 1.63854 | 55.45 | |
| H-ZK11 | CDGM | 1.63854 | 55.446553 | |
| N-SK18 | Schott | 1.63854 | 55.423596 | |
| SK18A | Schott | 1.63854 | 55.423596 | |
| BSM18 | Ohara | 1.638539 | 55.384768 | |
| S-BSM18 | Ohara | 1.638539 | 55.380028 | |
| M-PCD55AR | Hoya | 1.63858 | 55.18 | |
| MP-PCD55AR | Hoya | 1.63858 | 55.18 | |
| LACL1 | Hoya | 1.640851 | 56.835319 |