Department of Physics

Department News

Colloquium Announcement for February 8, 2019 (Speaker: Dr. Uttam Mana)

Feb 7, 2019

Dielectric Nanophotonics: the quest for lossless optical devices

Speaker: Dr. Uttam Mana
Date: Friday, February 8, 2019
Time: 4:00 P.M.(
Room: 205 Currens Hall

Nanoplasmonics is usually associated with noble metals that can confine light beyond the diffraction limit leading to unprecedent enhancement of the electric field with potentials to develop nanoscale optical interconnects, optical cloaking and super-resolution imaging,etc. However, overcoming the diffraction limit comes at a price - the high level of losses associated with free carriers in metals, limiting the efficiency of the optical devices. In this talk, I will discuss how resonant excitation of high-index dielectric nanostructures can pave an alternative route towards future nanophotonic devices because of their reduced dissipative losses and large resonant enhancement of both electric and magnetic near-fields. More specifically, I will focus on the discovery of the electrodynamic "anapole mode" (i.e. "without poles" in Greek) as a non-radiating source in high index dielectric materials. Subsequently, I will report the first experimental demonstration of electrodynamic anapoles in single silicon nanosphere (diameter ~ 160 nm) in our laboratory.

About the speaker:
Dr. Uttam Manna is an Assistant Professor of Physics, at Illinois State University. His research aims at understanding optical phenomena on the nanometer scale through a two-step process. First, confine light by classical means i.e. focus light using microscope objectives beyond the paraxial approximation. Then use the confined light as a probe to investigate resonance phenomena (electric and magnetic) in metal nanoparticle based structures.They also study the interaction of light with other nanoscale systems such as quantum dots, rare earth elements, etc.