A Babinet compensator illuminated with the mercury green line,

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

\lambda = 546.1\ \text{nm}

, is used between crossed polarisers to test an unknown transparent sample. Inserting the sample shifts the dark-band pattern by

0.60

of the spacing between adjacent bands. ((a)) Give the sample's retardance in waves and in radians. ((b)) Taking

|n_e - n_o| = 0.0091

for quartz (as at

589\ \text{nm}

), find the thickness of quartz that would give the same retardance at this wavelength.