邀请人： 周发然 副研究员（9677）

报告摘要：

Polaritons—hybrid quasiparticles arising from strong light–matter coupling—exhibit extreme electromagnetic confinement. When combined with the high tunability and versatile stacking of two-dimensional quantum materials, they provide unprecedented opportunities to engineer emergent quantum phases [1,2].

In this talk, I will present our recent advances in the infrared nano-optics of quantum materials, enabled by a custom-developed cryogenic scattering-type scanning near-field optical microscope (s-SNOM). I will first introduce the design and capabilities of our home-built s-SNOM platform. I will then demonstrate how the plasmonic response is highly sensitive to the underlying moiré potential landscape, allowing us to challenge the widely accepted notion of moiré ferroelectricity [3,4]. Finally, I will demonstrate that hyperbolic phonon polaritons can be harnessed to enhance vacuum fluctuations, through which we successfully engineer the superfluid density of adjacent superconducting layers [5]. These results establish polaritons as a powerful platform for probing, controlling, and designing quantum phases in vdW heterostructures.

[1] DN. Basov et al., Science 354, aag1992 (2016).
[2] S. Zhang et al., Phys. Rev. Lett. 136, 136904 (2026).
[3] S. Zhang et al., Phys. Rev. X 15, 011019 (2025).
[4] S. Zhang et al., Nature Commun. 14, 6200 (2023).
[5] I. Keren†, T. A. Webb†, S. Zhang† et al., Nature 650, 864 (2025).

报告人简介：
Shuai Zhang is an assistant professor in the Department of Physics at Fudan University. He received his Ph.D. from Fudan University and subsequently worked as a postdoctoral researcher and associate research scientist at Columbia University. His research focuses on infrared and terahertz nano-optics of quantum materials. He has developed advanced cryogenic near-field optical microscopy techniques to probe and control quantum phenomena at the nanoscale.