Controlling light with optical metasurfaces

Speaker: Professor Mikael Käll
Affiliation: Chalmers University of Technology, Gothenburg, Sweden

Abstract

An optical metasurface constitute a dense layer of sub-wavelength particles that have been designed to shape the phase and polarization distribution of a transmitted or reflected light wave, thereby offering a powerful route towards a huge variety of “flat” optical components. After introducing the basic concepts of optical metasurfaces, I will discuss some of our recent works in the area, including tiny lasers integrated with metaoptics and microparticles equipped with metasurfaces that deflect light and alter its polarization state. In the latter case, conservation of linear and angular photon momentum results in recoil forces and torques that allows one to construct miniature "metavehicles" able to navigate across a surface in water under plane-wave illumination while being steered through the incident polarization. Depending on how the metasurface is constructed, a microparticle can be optimized for different behaviors and functionalities, thereby opening the door to novel fundamental studies and applications in fields like microrobotics, micromachines, and active matter.

Biography:

Mikael Käll is an experimental physicist focusing on fundamental and applied nanooptics and biophotonics. His current research projects deal with the physics and applications of optical metasurfaces and optical forces. He has previously worked with topics like surface-enhanced Raman scattering, plasmonic biosensors, optical antennas, bioimaging, and strongly correlated electron systems. He has co-authored more than 200 journal papers that have been cited more than 25000 times to date.