21. Index of refraction is also composition-dependent and influences the extraction efficiency of photons from the material.22. Reflection depends on differences in index of refraction . 23. Each ring has a different index of refraction . 24. DPS has a conventional positive index of refraction , while the DNG has a negative refractive index. 25. The first experimental confirmation of negative index of refraction occurred soon after, also at microwave frequencies. 26. An example of a plasma with an index of refraction less than unity is Earth's ionosphere. 27. So it is as if gravity increased the index of refraction of space near massive bodies. 28. Pure titanium dioxide has a very high index of refraction and an optical dispersion higher than diamond. 29. For X-rays a concave lens focuses the X-rays because the index of refraction is slightly below unity. 30. In wavelength ranges where a medium has significant absorption, the index of refraction can increase with wavelength.
