A helium-neon laser beam ( nm in vacuum) travels inside a glass block of index and…

PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Wave propagation and light in media · Wave propagation and light in media

Optics and Photonics, Ch Reflection and transmission at interfaces

Problem

A helium-neon laser beam (

\lambda = 633

nm in vacuum) travels inside a glass block of index

n = 1.52

and strikes the glass–air (

n = 1.00

) boundary at

50.0^\circ

from the normal, well past the critical angle. ((a)) Confirm that this angle exceeds the critical angle. ((b)) Find the penetration depth

d_{\mathrm{ev}}

of the evanescent wave beyond the surface.