Topological Nanophotonics: Toward Robust Quantum Circuits

Abstract

In the last five years, the combination of advances in nanofabrication and a series of ingenious design ideas has enabled the implementation of topological concepts into nanophotonic platforms. In parallel, an unprecedented amount of research effort is being devoted to quantum technologies, with quantum information processing promising exponentially better performance than its classic counterpart for certain tasks. Nanophotonics is bound to play a key role in quantum information technologies given its compactness, low-power requirements, room-temperature operation, and the inherent high speed and low noise of photons. However, the scalability of quantum information systems in integrated photonic platforms is limited by scattering loss and other errors from random fabrication imperfections. The remarkable robustness to disorder and imperfections manifested by photonic states in topological systems emerges as a fascinating research avenue to tackle this issue. Furthermore, the ease of engineering and fabricating nanophotonic platforms with distinctive geometries and symmetries that can effectively generate and transport complex quantum states makes nanophotonics an ideal platform in which to realize topological protection of quantum photonic states. This article highlights the pioneering experimental efforts to understand the potential of topological protection on quantum photonic states and to outline a path toward robust quantum circuits.