Tuning Topology of Photonic Systems with Transparent Conducting Oxides

Abstract

Precise control over photonic states can be achieved in pre-engineered materials, like photonic crystals and meta-structures. However, high fabrication precisions are required due to the sensitivity of such states to different perturbation channels. Hence photonic states that immune to disorder in the system is in high demand. In this work, we propose a hybrid platform that integrates tunable transparent conducting oxides (TCOs) and a standard silicon-on-insulator waveguide technology, to achieve ultrafast all-optical control of the topology of photonic states. Particularly, we demonstrate that ultrafast control of coupling between ring resonators with integrated TCO modulators enables a synthetic gauge magnetic field and therefore provides ultrafast control of topology protection. The approach can be used for the realization of topological phase transitions, an essential component of several emerging photonic applications, including topologically protected optical modulators and switches.

Recent advances in 2D, 3D and higher-order topological photonics

“…Therefore, reconfigurable topological systems that support topological phase transitions that can be manipulated are essential. Dynamic control of topological phase transitions has been achieved using liquid crystals 228 , a phase-change material under temperature variation 229,230 and transparent conducting oxides under optical pumping 231 . A reconfigurable photonic topological system that supports selective propagation of topological edge modes under mechanical modulation was demonstrated using a bianisotropic photonic crystal 150 .…”

Topological phases in ring resonators: recent progress and future prospects

“…Similar tuning of the effective magnetic flux in ring-shaped lattices enables the observation of the Hofstadter butterfly via the lattice's scattering resonances [78,79]. There are recent proposals to implement phase shifters throughout the entire lattice in order to tune its topological properties, thereby enabling one to switch the topological edge states on or off or reroute them between different output ports [71,80,81]. Zhao et al [82] demonstrated controllable rerouting of topological states in the quantum Hall resonator lattice using structured bulk gain.…”

Topological phases in ring resonators: recent progress and future prospects

“…Similar tuning of the effective magnetic flux in ring-shaped lattices enables the observation of the Hofstadter butterfly via the lattice's scattering resonances 69,70 . There are recent proposals to implement phase shifters throughout the entire lattice in order to tune its topological properties, thereby enabling one to switch the topological edge states on or off or reroute them between different output ports 60,71,72 . Zhao et al demonstrated controllable re-routing of topological states in the quantum Hall resonator lattice using structured bulk gain 73 .…”