Broadband Topological Slow Light through Higher Momentum-Space Winding

Abstract

Slow-light waveguides can strongly enhance light-matter interaction, but suffer from narrow bandwidth, increased backscattering, and Anderson localization. Edge states in photonic topological insulators resist backscattering and localization, but typically cross the bandgap over a single Brillouin zone, meaning that slow group velocity implies narrow-band operation. Here we show theoretically that this can be circumvented via an edge termination that causes the edge state to wind many times around the Brillouin zone, making it both slow and broadband.

Topological photonics: Where do we go from here?

“…Nevertheless, the periodic modulation of this lattice has topological edge states on its exterior and on its internal edges. Topological photonics can also offer new ideas that have no counterparts in other physical systems, such as the recent proposal [38] for broadband topological slow light through higher momentum-space winding, which can greatly enhance light-matter interactions.…”

All-optical tunable slow-light based on an analogue of electromagnetically induced transparency in a hybrid metamaterial

“…Slow light means to make an optical signal slow down and thus be able to control it. Slow light is always an interest topic for researchers to utilize its full potential in optical buffer, switching, memory and quantum optics, where the full control of the speed of light is necessary 1 . So far, most of the approaches to obtain slow-light effect rely on the strong material dispersion based on nonlinear optical processes, such as electromagnetically induced transparency (EIT) 2 , stimulated Brillouin scattering (SBS) 3 , coherent population oscillations (CPO) 4 , stimulated Raman scattering (SRS) 5 , and optical parametric amplification (OPA) 6 .…”

Thouless pumping in disordered photonic systems

“…Adiabatic charge pumps 1 – 4 are an important class of topological systems, as they can exhibit robust transport and provide a physically intuitive mathematical mapping between a one-dimensional system and the intrinsically two-dimensional quantum Hall effect 5 . Moreover, photonic realizations of such systems represent alternatives to two-dimensional photonic topological insulators with chiral edge states 6 – 17 for achieving compact on-chip slow-light waveguides 18 – 28 . In the traditional electronic picture of adiabatic charge pumps, a system with a uniformly filled valence band is periodically modulated such that after a complete cycle, each localized Wannier state in the occupied band has adiabatically evolved to be transported by exactly one unit cell.…”