Linearly polarised light at to the horizontal passes through an ideal half-wave plate…

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

Linearly polarised light at

10^\circ

to the horizontal passes through an ideal half-wave plate (

\Gamma = \pi

) with its fast axis set at

35^\circ

to the horizontal. A student writes: "The plate adds its fast-axis angle to whatever comes in. The input is at

10^\circ

and the fast axis is at

35^\circ

, so the output is at

10^\circ + 35^\circ = 45^\circ

to the horizontal." ((a)) Explain the error in this reasoning. ((b)) Give the correct output angle to the horizontal.