Abstract
Since the isolation of graphene, van der Waals heterostructures — and their twisted counterparts in particular — have become a uniquely fertile ground for exploring phenomena inaccessible in conventional systems. Reduced dimensionality, nontrivial topology, quantum geometry, and strong correlations collectively govern the response of these materials to external fields — making them both a laboratory for fundamental discovery and a platform for next-generation optoelectronic technologies. In the first part of the presentation, I will introduce terahertz-driven magnetotransport as a new multi-messenger probe of quantum materials. I will show that terahertz excitation drives graphene into the hydrodynamic regime, giving rise to viscous photoconductivity — a fundamentally new type of the photoresponse with no analogue in conventional materials [1]. I will then demonstrate that moiré superlattices exhibit giant terahertz photoresistance, revealing transport regimes dominated by electron-electron interactions [2,3]. Finally, I will show how polarization-resolved and thermoelectric photocurrent measurements can fingerprint the quantum ground state of correlated moiré phases - providing direct access to their quantum geometry and orbital magnetic moments. In the second part of the talk, I will turn to quantum sensing of light. I will begin by presenting high-Tc superconductors as a platform for single-photon detection, offering a practical route to scalable sensing above liquid helium temperatures [4]. I will then show that correlated insulator states in magic-angle graphene form the active element of a new class of ultra-sensitive broadband hot electron bolometers spanning the mm-wave to far-IR domain. Finally, I will discuss Josephson junctions based on low-density two-dimensional materials as a potential route toward single-photon detection at terahertz frequencies — one of the most challenging frontiers in quantum sensing of light.
[1] M. Kravtsov, “Viscous terahertz photoconductivity of hydrodynamic electrons in graphene,” Nature Nanotechnology 20, 51–56 (2025).
[2] A. L. Shilov, “High-Mobility Compensated Semimetals, Orbital Magnetization, and Umklapp Scattering in Bilayer Graphene Moiré Superlattices,” ACS Nano 18, 11769–11777 (2024).
[3] A. L. Shilov, “Interaction-limited conductivity of twisted bilayer graphene revealed by giant terahertz photoresistance,” arXiv:2509.02552 (2025).
[4] I. Charaev, D.A. Bandurin, “Single-photon detection using high-temperature superconductors,” Nature Nanotechnology 18, 343–349 (2023).
[5] X. Zhou, “Gate-Tunable Photoresponse of Graphene Josephson Junctions at Terahertz Frequencies,” arXiv:2604.00409 (2026).
Anyone interested is welcome to attend.