Question

We consider a beam of light having a propagation direction along ?̂ and a linear polarization making an angle ? with respect to ?̂. We place a retardation plate normal to the beam. The slow axis is along ?̂ and it has a phase delay of ? with respect to the fast axis. The beam of light is considered as a monochromatic plane wave.

(a)Write the mathematical expression of the electric field corresponding to the incident beam as a function of ?.

(b) What should be the sign of ?? (? = relative phase difference between waves)

(c) Find a condition on ? and ? such that the polarization will be circular after passing through the retardation plate. Consider the smallest possible value for ?, and give the expression of the electric field after the plate. What kind of phase plate is it correspond to?

(d) What is the handedness of the polarisation?

(e) We would like to reverse the handedness of the polarization by using an extra retardation plate. What should be the phase delay of the new plate? What kind of phase plate is it correspond to? Show that the orientation of the plate axes is not important?

*We will suppose that the slow axis makes angle ? with ?̂. We define ?̂′ and ŷ′ the axes of the plate. Express the field in this new basis.

Answer 1