Refraction of space-time wave packets: III. Experiments at oblique incidence

TL;DR

This paper experimentally investigates how space-time wave packets refract at oblique angles, revealing tunable group velocities and demonstrating a novel 'blind synchronization' method for simultaneous arrival at different locations.

Contribution

It provides the first experimental verification of oblique incidence refraction phenomena of space-time wave packets and introduces a proof-of-principle for blind synchronization.

Findings

Group velocity of refracted wave packets can be tuned by incidence angle

Experimental confirmation of predicted refraction phenomena at oblique incidence

Demonstration of blind synchronization for simultaneous arrival at multiple receivers

Abstract

The refraction of space-time (ST) wave packets at planar interfaces between non-dispersive, homogeneous, isotropic dielectrics exhibit fascinating phenomena, even at normal incidence. Examples of such refractive phenomena include group-velocity invariance across the interface, anomalous refraction, and group-velocity inversion. Crucial differences emerge at oblique incidence with respect to the results established at normal incidence. For example, the group velocity of the refracted ST wave packet can be tuned simply by changing the angle of incidence. In paper (III) of this sequence, we present experimental verification of the refractive phenomena exhibited by ST wave packets at oblique incidence that were predicted in paper (I). We also examine a proposal for 'blind synchronization' whereby identical ST wave packets arrive simultaneously at different receivers without \textit{a priori} knowledge of their locations except that they are all located at the same depth beyond an interface between two media. A first proof-of-principle experimental demonstration of this effect is provided.