- Why is the crystal shaped the way it is?
- Why does the crystal appear to have a film/coating on the center of it.?
Nicolet iN10 Microscope
The backside of the crystal is hemispherical in shape to create the ATR affect.
Also a secondary effect of the hemispherical shape is that it creates an immersion effect that helps focus the source energy to a smaller spot size on the contact surface of the crystal.
The crystal has a reflective coating in the center to only allow source energy to enter at an area of the crystal to direct the energy at the correct incidence angle.