Topological phase singularities in atomically thin high-refractive-index materials
Abstract
Atomically thin transition metal dichalcogenides (TMDCs) present a promising platform for numerous photonic applications due to excitonic spectral features, possibility to tune their constants by external gating, doping, or light, and mechanical stability. Utilization of such materials for sensing or optical modulation purposes would require a clever optical design, as by itself the 2D materials can offer only a small optical phase delay - consequence of the atomic thickness. To address this issue, we combine films of 2D semiconductors which exhibit excitonic lines with the Fabry-Perot resonators of the standard commercial SiO/Si substrate, in order to realize topological phase singularities in reflection. Around these singularities, reflection spectra demonstrate rapid phase changes while the structure behaves as a perfect absorber. Furthermore, we demonstrate that such topological phase singularities are ubiquitous for the entire class of atomically thin TMDCs and other high-refractive-index materials, making it a powerful tool for phase engineering in flat optics. As a practical demonstration, we employ PdSe topological phase singularities for a refractive index sensor and demonstrate its superior phase sensitivity compared to typical surface plasmon resonance sensors.
Cite
@article{arxiv.2106.12390,
title = {Topological phase singularities in atomically thin high-refractive-index materials},
author = {Georgy Ermolaev and Kirill Voronin and Denis G. Baranov and Vasyl Kravets and Gleb Tselikov and Yury Stebunov and Dmitry Yakubovsky and Sergey Novikov and Andrey Vyshnevyy and Arslan Mazitov and Ivan Kruglov and Sergey Zhukov and Roman Romanov and Andrey M. Markeev and Aleksey Arsenin and Kostya S. Novoselov and Alexander N. Grigorenko and Valentyn Volkov},
journal= {arXiv preprint arXiv:2106.12390},
year = {2022}
}