Vasily Kravtsov

Affiliation: ITMO University

Research interests: Two-dimensional quantum materials, ultrafast spectroscopy, nonlinear nano-optics
Title: Near-field spectroscopy and control of excitons in 2D van der Waals heterostructures.
Abstract: Atomically thin transition metal dichalcogenides (TMDs) are direct band gap semiconductors that host excitons with large binding energies and sizeable exciton – exciton interaction strength. When stacked into heterostructures, these materials acquire many unique optical properties associated with the interlayer coupling and formation of new excitonic and polaritonic states. Near – field spectroscopy provides an indispensable tool for studying such states, as well as their coupling, dynamics, and control. I w ill present results of our recent investigation of excitonic effects in van der Waals heterostructures via different near – field spectroscopy implementations including tip – enhanced spectroscopy and spectroscopy in the Fourier plane via evanescent wave coupling through a solid immersion lens. First, I will discuss the possibility of controlling the intralayer and interlayer excitons within a nanoscopic volume of TMD heterobilayers. Second, I will discuss experiments on probing and controlling exciton – polarito ns in all van-der-Waals heterostacks in the strong light-matter coupling regime.