Optical Silicon vs. Gallium Arsenide
Both optical silicon and gallium arsenide are non-glass optical ceramics. There are 13 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is optical silicon and the bottom bar is gallium arsenide.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 150 | |
| 85 |
| Knoop Hardness | 1130 | |
| 750 |
| Poisson's Ratio | 0.28 | |
| 0.31 |
Thermal Properties
| Melting Onset (Solidus), °C | 1560 | |
| 1400 |
| Specific Heat Capacity, J/kg-K | 700 | |
| 360 |
| Thermal Conductivity, W/m-K | 150 | |
| 47 |
| Thermal Expansion, µm/m-K | 3.0 | |
| 5.6 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.3 | |
| 5.3 |
| Light Transmission Range, µm | 1.2 to 15 | |
| 1.0 to 16 |
| Refractive Index | 3.5 | |
| 3.4 |
Common Calculations
| Stiffness to Weight: Axial, points | 35 | |
| 8.9 |
| Stiffness to Weight: Bending, points | 75 | |
| 28 |
| Thermal Diffusivity, mm2/s | 93 | |
| 25 |