Question

4) A laser beam shines up through a piece of glass of refractive index of 1.56 and reach the glass-air interface. A) At what range of incident angles will the laser beam not pass out of the glass and into air. Explain and show any calculations. Use your prediction to explain how a glass rod (or a glass fiber) can become a pipe to transmit light signals without losses out the side walls. Indicate any assumptions you made.

Answer 1

Sin theta/sin 90 degree = n_ain/n_glass = (1/1.56) theta = sin^-1(1/1.56) theta = 39.87 degree theta > 39.87 degree