A layer of magnesium fluoride ( ) is deposited on crown glass ( ) and viewed in…
PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Interference and diffraction · Interference and diffraction
Optics and Photonics, Ch Multiple-beam interference: thin films, multilayers and the Fabry-Perot etalon
Problem
A layer of magnesium fluoride (nf=1.38) is deposited on crown glass (ns=1.52) and viewed in reflection from air at θi=35∘ from the normal. For a component of vacuum wavelength λ=520 nm:
((a)) Use Snell's law to find the angle of refraction θt inside the coating.
((b)) Both interfaces here are reflections at an increasing index. Count the phases and find the smallest non-zero coating thickness for which this wavelength is reflected most strongly.