Question

What is the angle of fast axis if we want to use a quarter-wave plate to create circularly polarized light from linearly polarized light.

Answer 1

When linearly polarised light is incident on a quater wave plate at 45° to the optic axis, then the light is divided into two equal electric field components, 'o' and 'e', 'o' is ordinary and is retarded by a quarter wavelength by the plate resulting in circularly polarised wave. Hence 'o' is slow axis and 'e' is fast axis. 'e' is along the optic axis that is angle between fast axis and optic axis is 0 degrees. Hence to get circularly polarised light from quater waveplate, incident wave should be at 45 degrees to fast axis.

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