Goos-Hänchen shift of a transmitted light beam in frustrated total internal reflection for moderately large gap widths

Goos-Hänchen shift of transmitted light beam is studied in frustrated total internal reflection for moderately large gap widths. The traditional Artmann's formula is shown to be inapplicable in this case. An alternative approach of this value calculation is proposed. The presented result corresponds to the intuitively expected limit dependencies on the problem parameters.