A right-angle prism is made of dense flint glass with index of refraction
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A right-angle prism is made of dense flint glass with index of refraction n=1.62. One of its legs is coated with an antireflection layer so that an external laser beam of wavelength 633 nm enters the prism nearly normal to that leg. The beam then strikes the hypotenuse inside the prism.
For parts (a)–(c) assume the prism is in air (nair=1.00) and neglect dispersion.
(a) Using the geometry of a right-angle prism, express the angle ϕ that the beam makes with the normal to the hypotenuse in terms of the incidence angle θ0 of the laser beam in air measured from the normal to the entrance face.
(b) Determine the minimum value of θ0 for which the beam undergoes total internal reflection at the hypotenuse.
(c) If the entrance angle θ0 is set 5∘ larger than the value found in part (b), calculate the resulting angle of reflection inside the prism at the hypotenuse and interpret what this implies for the efficiency of the prism as a mirror.