Table 1.
Pressure induced changes in refractive index as measured with helium yellow radiation of 5875.62 Å
| Material | Refractive index, μHe |
Specimen thickness, t0 |
Pressure, P |
Thickness change, −Δt/t0×103 |
Observed change in fringe number −ΔN |
Change in refractive index Δμ×105 |
|---|---|---|---|---|---|---|
| Cm | bars | |||||
| KBr | 1.560 | 0.3210 | 966.1 | 2.118 | 11.3 | 227 |
| NaCl | 1.546 | .6748 | 963.6 | 1.348 | 21.6 | 115 |
| LiF | 1.392 | .5683 | 963.2 | .349 | 9.4 | 0 |
| MgO | 1.738 | .3970 | 960.8 | .190 | 6.8 | −17 |
| Diamond | 2.418 | .4037 | 960.0 | .058 | 3.4 | −11 |
| Quartz: | ||||||
| ω | 1.545 | .5112 | 957.6 | .944 | 6.9 | 103 |
| ϵ | 1.554 | .5112 | 961.5 | .948 | 7.5 | 107 |
| Sapphire: | ||||||
| ω | 1.769 | .5659 | 961.8 | .105 | 6.2 | −14 |
| ϵ | 1.760 | .5659 | 957.6 | .105 | 6.2 | −14 |
| Fused SiO2 | 1.458 | .4967 | 960.2 | .865 | 7.3 | 83 |
| BSC 517/645 | 1.517 | .6693 | 960.1 | .717 | 8.9 | 70 |
| Plate glass | 1.518 | .6566 | 960.0 | .723 | 9.1 | 69 |