Adarsh VASISTA, IISER, India

Adarsh VASISTA, from the Department of Physics in Indian Institute of Science Education and Research (IISER) Bhopal, INDIA, will give an invited seminar entitled “Engineering Light-Matter Interaction at the Nanoscale: A story told through the lens of optical phase and wavector” on Friday, December 12, at 02:00 p.m. in Pierre Cotton’s room of Institut Fresnel.

Abstract : Understanding and harnessing the way light interacts with matter is at the heart of nanophotonics. The interaction of light with nanoscale matter depends crucially on the shape, size, and material properties like dielectric permittivity. By tuning the wavelength of incident light to match the resonant modes of nanostructures we can enhance significantly enhance scattering or absorption of light. This ability to control light-matter interaction has enabled a broad range of applications, from the development of nanoscale heat sources to single molecule detection. In the first part of the talk, I will discuss how resonant scattering and the resulting electric-field enhancement around nano- and micro-cavities can be exploited to amplify and direct molecular emission. Using metal-film–coupled plasmonic nanowires and dielectric microspheres as examples [1,2], I will demonstrate the strengths of wavevector imaging and spectroscopy (also known as back-focal-plane imaging and spectroscopy) in revealing the rich polarization structures of these systems. I will also briefly address the potential of dielectric microspheres for achieving strong molecule–cavity coupling down to the monolayer limit [3,4]. In the second part of the talk, I will shift focus to our effort to understand, engineer, and utilize light absorption in mettalic nanostructures as a means of generating nanoscale heat. I will highlight our use of the thermo-optical effect, combined with quantitative phase imaging, to visualize non-steady-state thermak fiels [5,6].