Exciton-Polaritons and Localized Surface Plasmons: Light-Matter Interactions at Different Scales

Date: 
Thursday, January 29, 2015 - 4:00pm to Friday, January 30, 2015 - 12:00pm
Speaker: 
Esther Wertz
Speaker's Institution: 
University of Michigan

Colloquium

Thursday, January 29th, 2015

4:00pm
100 Willamette

Research Talk

Friday, Janauray 30th, 2015
10:00am
240D Willamette
 

Abstract

Light interacts with matter through processes such as absorption, scattering and emission so that by monitoring the changes in these interactions we can learn about the nature of the light’s environment, and, conversely, we can use these interactions to manipulate light in new ways. In this seminar, I will discuss two systems in which I have investigated light-matter interactions. First, I will talk about exciton-polaritons, quasi-particles arising from the strong coupling between quantum well excitons and cavity photons. The bosonic nature of these particles makes them good candidates to investigate the physics of Bose condensates in a solid state system, while their mixed light-matter nature allows us to optically manipulate them. In the second part of my talk, I will discuss localized surface plasmon resonances, and how we can unravel the coupling of light to a nano-antenna through single-molecule fluorescence imaging. This technique is a powerful tool to optically study structures beyond the diffraction limit by localizing isolated fluorophores and fitting the emission profile to the microscope point-spread function. By using the random motion of single dye molecules in solution to stochastically scan the surface, and by assessing emission intensity and density of emitters as a function of position, we show that the fluorophore emission location is strongly shifted upon coupling to the antenna, and that dyes can be coupled to nano-antennas at distances up to 90 nm away, i.e., much farther than the 10-20 nm plasmon enhancement length.