Amin Hashemi’s research while affiliated with University of Central Florida and other places

Topological quantum photonics explores the interaction of the topology of the dispersion relation of photonic materials with the quantum properties of light. The main focus of this field is to create robust photonic quantum information systems by leveraging topological protection to produce and manipulate quantum states of light that are resilient to fabrication imperfections and other defects. In this perspective, we provide a theoretical background on topological protection of photonic quantum information and highlight the key state-of-the-art experimental demonstrations in the field, categorizing them based on the quantum features they address. An analysis of the key challenges and limitations concerning topological protection of quantum states is presented. Importantly, this paper takes a thorough perspective look into what future research in this area may bring.

Understanding the interplay of non-Hermiticity and topology is crucial given the intrinsic openness of most natural and engineered systems and it has important ramifications in topological lasers and sensors. Intense efforts have been devoted to unveiling how non-Hermiticity may impact the most significant features of topological systems, but only recently it has been theoretically proposed that topological features could originate solely from the system's non-Hermiticity in photonic systems. In this work, we experimentally demonstrate the appearance of non-Hermitian topology exclusively from loss modulation in a photonic system that is topologically trivial in the absence of loss. We do this by implementing a non-Hermitian generalization of an Aubry-Andre-Harper model with purely imaginary potential in a programmable integrated photonics platform, which allows us to investigate different periodic and quasi-periodic configurations of the model. In both cases, we show the emergence of topological edge modes and explore their resilience to different kinds of disorder. Our work highlights loss engineering as a mechanism to generate topological properties.

We report the experimental realization of non-Hermitian topology purely based on loss modulation in a programmable silicon photonics platform. Our results show the robustness of the topological mode to perturbations in the loss.