申論題

9. To study the interference of two beams, instead of using two slits, one can use one light source and a reflecting surface to construct an interferometer, as shown in the figure. Suppose that the incidence angle is always big enough to assume that the intensities of the direct beam and reflected beam are very close to each other.

(a) If the reflecting mirror is a piece of glass with index of refraction n> 1, how would the interference pattern differ, qualitatively, from double-slit interference pattern with the same separation between the two sources? What is the reason for the difference? (5%)