Reporter: Prof. Jia min Quan

Time: 2024-09-26 10:00-11:00

Place: The Large Conference Room on the second floor, B4

Abstract

The study of light-matter interaction is at the forefront of advanced optoelectronic devices, opto-quantum devices, and fundamental physics. The decreased dimensionality of two-dimensional (2D) materials leads to enhanced environmental sensitivity and light-matter interaction, providing an excellent platform for investigating new optical phenomena. In this seminar, I will discuss two different strategies to control light-matter interaction in 2D semiconductors. The first strategy focuses on the materials themselves, employing various techniques, including heterostructures, strains, and defects, to manipulate their intrinsic properties and alter their interaction with light. Specifically, I will highlight how stacking two monolayers together creates the moiré superlattice to renormalize light-matter interaction in 2D semiconductors. The second strategy involves leveraging optical cavities to control local light density, thereby influencing the interaction between light and matter. In the weak coupling region, I will present the discovery of a series of dark exciton resonances achieved by coupling a monolayer semiconductor to plasmonic nanocube cavities. Additionally, I will introduce a novel resonant geometry characterized by a high-quality factor and an ultrasmall mode volume, which allows for achieving ultra-low threshold interlayer exciton lasing. In the strong coupling region, I will reveal the emergence of light-matter hybrids in the layered magnetic semiconductor CrSBr, even without external cavity mirrors. By extending correlations between magnetic, electronic, and optical properties to deep states within the material's band gap, I will demonstrate that hybrid light-matter excitations can significantly enhance the spectral bandwidth of magneto-optic responses.

Biography

Bio: Prof. Jia min Quan, Professor of the School of Physical Sciences and Engineering of Tongji University, a national-level young talent, a leading young talent in Shanghai, and a talent in Pujiang, Shanghai. The research mainly focuses on the interaction between light and matter at the nanoscale, covering two-dimensional materials, nanophotonic devices and the cross-application of the two. In recent years, 30 papers have been published, of which 8 articles have been published in journals such as Nature, Nature Materials (cover), PNAS, Nano Letters, etc., and participated in the compilation of an English monograph. The total number of citations in the paper exceeds 2,400 times.