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(Solved): 5. Two glass plates are separated by an air gap of thickness d, as shown in the diagram below. A l ...
5. Two glass plates are separated by an air gap of thickness , as shown in the diagram below. A light ray is incident on the right surface of the first plate at an angle that is greater than the critical angle. Estimate the distance such that the evanescent was will bridge the gap so that approximately of the light can pass through the gap and continue to pass through the second plate of glass.
Expert Answer
A light ray is incident on the right surface of the first plate at an angle?Total internal reflection happens when light is transmitted at an angle larger than the critical angle from a medium with a higher refractive index to one with a lower one. In the lower refractive index material, there is likewise an evanescent wave, but its strength diminishes exponentially as one moves away from the interface.The evanescent wave can extend across the space and let some light through if a second interface is situated close enough to the first interface. The angle of incidence and the refractive indices of the two mediums determine how far the evanescent wave can span the distance.