Photonic Jackiw-Rebbi states in all-dielectric structures controlled by bianisotropy

Electric and magnetic resonances of dielectric particles have recently uncovered a range of exciting applications in steering of light at the nanoscale. Breaking of particle inversion symmetry further modifies its electromagnetic response giving rise to bianisotropy known also as magneto-electric coupling. Recent studies suggest the crucial role of magneto-electric coupling in realization of photonic topological metamaterials. To further unmask this fundamental link, we design and test experimentally one-dimensional array composed of dielectric particles with overlapping electric and magnetic resonances and broken mirror symmetry. Flipping over half of the meta-atoms in the array, we observe the emergence of interface states providing photonic realization of the celebrated Jackiw-Rebbi model. We trace the origin of these states to the fact that local modification of particle bianisotropic response affects its effective coupling with the neighboring meta-atoms which provides a promising avenue to engineer topological states of light.Comment: 5 pages, 5 figure

Nonlinear Control of Electromagnetic Topological Edge States

Topological photonics has emerged recently as a smart approach for realizing robust optical circuitry, and the study of nonlinear effects is expected to open the door for tunability of photonic topological states. Here we realize experimentally nonlinearity-induced spectral tuning of electromagnetic topological edge states in arrays of coupled nonlinear resonators in the pump-probe regime. When nonlinearity is weak, we observe that the frequencies of the resonators exhibit spectral shifts concentrated mainly at the edge mode and affecting only weakly the bulk modes. For a strong pumping, we describe several scenarios of the transformation of the edge states and their hybridization with bulk modes, and also predict a parametrically driven transition from topological stationary to unstable dynamic regimes.This work was partially supported by the Australian Research Council and by the Air Force Office of Scientific Research under Grant No. FA2386-16-1-0002. The numerical calculations are supported by the Russian Science Foundation (Grant No 16-19-10538). Experimental studies of nonlinear response are supported by the Russian Foundation for Basic Research (Grant No. 18-32-20065). Experimental studies of linear response are supported by the Ministry of Education and Science of the Russian Federation (Zadanie No. 3.2465.2017/4.6). The work of A. V. Y. was supported by the Government of the Russian Federation (Grant No. 074-U01) through the ITMO Fellowship

Subwavelength topological edge states in optically resonant dielectric structures

We suggest a novel type of photonic topological edge states in zigzag arrays of dielectric nanoparticles based on optically induced magnetic Mie resonances. We verify our general concept by the proof-ofprinciple microwave experiments with dielectric spherical particles, and demonstrate, experimentally, the ability to control the subwavelength topologically protected electromagnetic edge modes by changing the polarization of the incident wave.This work was supported by the Australian Research Council, the Government of the Russian Federation (Grant No. 074-U01), the Dynasty Foundation (Russia), and the Russian Fund for the Basic Research. A. P. S. acknowledges a support of the SPIE scholarship. A. N. P. acknowledges a support of the President Grant of the Russian Federation (No. MK-6029.2014.2)