Effects due to Total Internal Reflection

Total internal reflection, once established, produces a wide range of everyday and technological effects, covered one at a time in this subsection: the sparkle of a cut diamond; the mirage (and its reverse, looming) seen over hot or cold ground; right-angle and $180°$-turning prisms used instead of silvered mirrors; the bright circular 'Snell's window' seen by an underwater observer looking up; the light-guiding action of an optical fibre; and the acceptance angle and numerical ape …