A ray of non-polarized light incidents on a uniaxial calcite crystal at an angle of to the normal from the air. The optical axis has a 60 deg angle to the surface in the plane of the incident. For calcite: ?0=1.65836 and ??=1.48641.

(a) Please calculate the separation angle between ordinary ray (o-ray) and extraordinary rage (e-ray) in terms of light energy propagation direction when

(b) Please calculate the incident angle when the separation angle between ordinary ray (o-ray) and extraordinary rage (e-ray) is zero in terms of light energy propagation direction.