Mercedeh Khajavikhan's research covers a wide spectrum in optics, including topics such as nanolasers, plasmonics, silicon photonics and active photonic systems. She is particularly well known for her work in the field of topological photonics and PT symmetry.

In her DLS lecture, Prof. Khajavikhan spoke about a very recent breakthrough, ‘Guiding Trojan Beams Using Lagrange Points’. The guided transmission of optical waves is critical for light-based applications in modern communication, information processing and energy generation systems. Traditionally, the guiding of light waves in structures such as optical fibers has been predominantly achieved through the use of total internal reflection. In periodic platforms, a variety of other physical mechanisms can also be deployed to transport optical waves. However, transversely confining light in fully dielectric, non-periodic and passive configurations remains a challenge in situations where total internal reflection is not supported. Mercedeh Khajavikhan discussed how this challenge can be overcome by guiding Trojan beams through Lagrangian points, a special class of equilibrium positions similar to those responsible for the capture of Trojan asteroids in celestial mechanics. This can be achieved in arrangements in which optical Coriolis forces induce guiding channels even at locations where the refractive index landscape is defocussing or completely inconspicuous. In addition, Mercedeh Khajavikhan outlined how the findings could have implications beyond the usual optical waveguide systems and could also be applicable to other physical systems such as acoustics, electron beams and ultracold atoms.

Mercedeh Khajavikhan is a professor at the Department of Electrical and Computer Engineering at the University of Southern California in Los Angeles, with a joint appointment at the Department of Physics and Astronomy.

The lecture is available in full on our Youtube channel.