The rise of quantum science and technology motivates photonics research to seek novel platforms to actively control light on the chip and to induce strong light-matter interactions to facilitate nonlinear and quantum behaviors at moderate light intensities. Topological photonics endows light with synthetic spin-like degrees of freedom and thus offers an ideal platform to manipulate photon qubits on the fly, and, at the same time, provides these states of light with topological robustness.
In the first part of my talk, I will describe how pseudo-spin degree of freedom is introduced by symmetry engineering in silicon-based topological photonic nanostructures. I will present theoretical and experimental results that show how the synthetic gauge fields can be produced to selectively act on spin-full guided modes, e.g., to produce single qubit gate operations. I will also show how the synthetic gauge fields allow creating topologically robust waveguides as well as higher-order topological modes, which represent low-dimensional topological cavities. Our experimental results demonstrating integration of spectrally tunable quantum emitters into a topological silicon-on-insulator device will be presented .
In the second part of my talk, I will discuss light-matter interactions in topological photonic nanostructures integrating van der Waals materials. First, I will show that, thanks to the spin-polarized nature of guided modes in topological waveguides, one can selectively couple forward and backward propagating modes to the valley polarized excitons in monolayer transition metal dichalcogenides . The resultant exciton-polaritons thus allow a directional transfer of the valley degree of freedom and spin of excitons, which are guided along with the electromagnetic wave. A pathway toward active control of topological states in such systems with the use of reconfigurable gauge fields will be presented . Second, I will demonstrate that a similar approach can be applied to phonons in mid-IR, where transverse vibrations in an hBN film can be directionally guided by the spin-polarized topological modes in a resilient manner, avoiding backscattering due to sharp bends . Our approach to use structured/spin-polarized light to control light-matter interactions offers a new pathway to manipulate solid-state excitations and their degrees of freedom with topological modes, which can find application in spintronics/valleytronics and in quantum phononic devices.
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Alexander B. Khanikaev received his PhD degree in Physics from the M. V. Lomonosov Moscow State University in 2003. After graduation Dr. Khanikaev spent five years at the Department of Electrical and Electronic Engineering of Toyohashi University of Technology, Japan, as a postdoctoral scholar and then as a senior researcher, where he worked on the topics of magnetic photonic crystals and plasmonic nanostructures. From 2009 Dr. Khanikaev held a position of a research associate at the Department of Physics, University of Texas at Austin, where he contributed to the fields of infrared photonics and plasmonic and all-dielectric metamaterials, biosensing, and graphene photonics. In 2012 he pioneered the concept of photonic topological insulators. In 2013 Dr. Khanikaev joined the City University of New York as a faculty member. Dr. Khanikaev’s research focus is on design and experimental studies of photonic nanostructures and metamaterials. His current research interests and directions include topological photonics and light-matter interactions in novel and engineered optical materials for quantum photonics applications. Presently Dr. Khanikaev is a Full Professor at the City College, Electrical Engineering Department, and at the Graduate Center and the Advanced Science Research Center of CUNY. He is a Fellow of the Optical Society of America (Optica), class 2021, and a recipient of the NSF Special Creativity Award (2021).