Quantum boomerang effect of light

TL;DR

This paper reports the first experimental observation of the quantum boomerang effect with light in a disordered photonic lattice, revealing that optical loss can enhance this phenomenon and offering new insights into light-matter interactions.

Contribution

It provides the first experimental demonstration of the quantum boomerang effect of light in a disordered medium using on-chip photonic lattices, and shows optical loss can enhance the effect.

Findings

Observation of light returning to its origin after initial displacement

Optical loss accelerates the quantum boomerang effect

Confirmation of Anderson localization in the system

Abstract

The quantum boomerang effect is a counterintuitive phenomenon where a wave packet, despite having an initial momentum, returns to its starting position in a disordered medium. However, up to now, the experimental exploration of this effect remains largely unexplored. Here, we report the experimental observation of the quantum boomerang effect of light. Our experiment is based on a one-dimensional disordered photonic lattice, which is composed of on-chip optical waveguides with engineered on-site random potential. We first characterize this optical disordered system by demonstrating the static Anderson localization of light beams. Next, through launching a kinetic light beam into the system, we observe that the light beam first moves away from its starting point, arrives at a maximum value, reverses its direction, and returns to its original position over time, confirming the observation of the quantum boomerang effect of light. Surprisingly, we find that optical loss, usually considered to be detrimental to optical experiments, can enhance the quantum boomerang effect by accelerating the light back to its original position. Our work provides new insights into the light-matter interactions in disordered medium and opens an avenue for future study of this phenomenon in nonlinear and many-photon contexts.