Comment on "Photonic tunneling time in frustrated total internal reflection"

This is a comment on Stahlhofen's paper [Phys. Rev. A 62, 012112 (2000)]. It is shown by stationary-phase theory that the Goos-Hanchen shift in frustrated total internal reflection (FTIR) is not independent of the group delay (or phase time in the literature). The group delay involves the contribution of Goos-Hanchen shift and is always larger than zero in FTIR. It is also shown that the group delay in the two-dimensional (2D) optical FTIR can be written in the same form as that of the group delay in the 1D quantum tunneling in the sense that the group delay is the derivative of the total phase shift with respect to the angular frequency.