Observable tachyons in the tunneling regime?

This is the authors' abstract. We don't add key points for this paper.

Some aspects are discussed of experiments reporting superluminal velocities of electromagnetic waves propagating across a photonic barrier. Emphasis is put on optical tunneling in frustrated total internal reflection while using the propagation of evanescent modes as guiding idea. This allows to distinguish between obvious and hidden time scales in tunneling by monitoring nonspecular deformations of the incoming beam. The possibility of using specially designed systems for a detailed study of these deformations is addressed.