Mechanical and Civil Engineering Seminar

Thursday February 9, 2017 11:00 AM

“Quantum Spillover, Chiral Plasmons and Controllable Quenching of Super-radiance in Deep Subwavelength Optical Coatings”

Speaker: Nicholas Xuanlai Fang, Mechanical Engineering, Massachusetts Intstitute of Technology
Location: Gates-Thomas 135
Recently, exciting new physics of plasmonics has inspired a series of key explorations to manipulate, store and control the flow of information and energy at unprecedented dimensions. In this talk I will report our recent efforts on controlling light absorption and emission process through quantum effects in sub-20nm scale coatings. For example, surface plasmons of different chirality can be excited in two dimensional materials that support transverse currents. We propose a method to optically excite and characterize the electromagnetic response and surface electromagnetic modes in a generic gapped Dirac material under pumping with circularly polarized light. The valley imbalance due to pumping leads to a net Berry curvature, giving rise to a finite transverse conductivity. Guided by our theoretical work, we argue the appearance of nonreciprocal chiral edge modes, their hybridization and wave guiding in a nanoribbon geometry, and giant polarization rotation in nanoribbon arrays. We also demonstrate experimentally ultrafast quenching of 2D molecular aggregates at picosecond timescale assisted by surface plasmons. Our analysis reveals that the metal-mediated dipole-dipole interaction increases the energy dissipation rate by at least five times faster than that predicted by conventional models. Our results can offer novel design pathways to the light-matter interaction in a variety of photon-exciton systems with applications such as high speed visible light communication.
Series Mechanical and Civil Engineering Seminar

Contact: Sonya Lincoln at 626-395-3385 lincolns@caltech.edu