Observation of localized flat-band modes in a quasi-one-dimensional photonic rhombic lattice

TL;DR

This paper reports the experimental observation of flat-band modes in a quasi-one-dimensional photonic lattice, demonstrating diffractionless propagation and potential for future studies involving synthetic gauge fields and photonic caging.

Contribution

The study provides the first experimental realization of flat-band modes in a photonic rhombic lattice using ultrafast laser inscription.

Findings

Observation of diffractionless propagation of flat-band modes

Experimental excitation of flat-band eigen modes

Potential for observing Aharonov-Bohm photonic caging in future work

Abstract

We experimentally demonstrate the photonic realization of a dispersionless flat-band in a quasi-one-dimensional photonic lattice fabricated by ultrafast laser inscription. In the nearest neighbor tight binding approximation, the lattice supports two dispersive and a non-dispersive (flat) band. We experimentally excite superpositions of flat-band eigen modes at the input of the photonic lattice and show the diffractionless propagation of the input states due to their infinite effective mass. In the future, the use of photonic rhombic lattices, together with the successful implementation of a synthetic gauge field, will enable the observation of Aharonov-Bohm photonic caging.