PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Polarisation and anisotropic media · Polarisation and anisotropic media
Optics and Photonics, Ch Birefringence and crystal optics
Problem
A Babinet compensator, used with sodium light of vacuum wavelength λ=589nm, shows a set of dark bands between crossed polarisers when the wedges are set with no sample present. An unknown birefringent sample is then inserted, and the whole band pattern is observed to shift by 0.25 of the spacing between adjacent bands.
((a)) State the sample's retardance in waves and in radians.
((b)) Given that quartz has ∣ne−no∣=0.0091 at 589nm, find the thickness of quartz that would give this same retardance.