Title: Unravelling the topological phase of light and matter: Physics and Device applications
Speaker: Dr. Abhishek Kumar, NTU, Singapore
Gmeet Link: https://meet.google.com/dwv-bavz-onc
Abstract: For many decades, physicists relied on the notion of symmetry breaking to distinguish different phases of matter. However, it has been recently shown that topology provides a universal way to classify the matter based on topological phases. Their hallmark feature is the appearance of edge states which are robust to backscattering at the interface between two materials of different topological phases. Recently, the concept of topology has been translated into the domain of photonics: topological photonics, with a grand vision to achieve robust and dissipation less transport of photons. The flexibility to implement engineered Hamiltonians has made topological photonics a unique platform to study topological phenomena and promises exceptional applications in integrated photonics. In this talk, I will present that how the topological phases of light in valley photonic crystal (VPC) give rise to unique functionalities in photonic devices. Leveraging the robustness of valley edge states, I developed terahertz topological photonic integrated platform, vital for realizing next generation 6G communication, high-speed on chip interconnects and exploring topological light-matter interactions. I will show that valley protected edge states combined with low loss all silicon platform yields ultra-high quality (Q) factor topological cavity with , whose resonance modes are immune from the imperfections and defects. Similar to photonic domain, the nontrivial topology in matters offer wealth of opportunities to improve our comprehension of the underlying physics. I will show that how ultrafast time-resolved terahertz spectroscopy can be used to elucidate new physics and probe the quasi-particles dynamics in topological materials. The new paradigm brought out by the topological phase of light and matter holds the potential to revolutionize various fields of natural science, including condensed matter physics, material science and photonics.