By Colbi Edmonds
As the lead principal investigator, Professor Siddharth Ramachandran (ECE) was awarded a Multidisciplinary University Research Initiative (MURI) grant to study the science and applications of singular light beams in the presence of spin-orbit interactions. Starting on June 1, 2020, Ramachandran will collaborate with co-PIs at Harvard and Stanford Universities. The team will experimentally as well as theoretically probe fundamental interactions between the spin and orbital angular momentum of light in optical fibers, free space and metamaterials.
In general, light can carry both orbital angular momentum (OAM) and spin angular momentum (SAM) that are related to wavefront rotation and polarization, respectively. This has led to several scientific and technological applications, including secure quantum communications, super-resolution microscopy, and alternative modalities of image processing and sensing. Ramachandran’s team will study spin-orbit coupling that provides a less-exploited degree of freedom to manipulate the linear and nonlinear properties of light carrying SAM and OAM, and manifests strongly in nanostructures, high numerical-aperture systems, and high index-contrast optical fibers. The project will focus on three interrelated topics: pairing topologically complex light with acoustic and optical phonons (which will rewrite design principles for fiber lasers), studying metasurfaces and artificial structures which are topologically complex and can create new device schematics for OAM/SAM beams, and researching topological invariants to inform the design of spin-orbit coupled optical fibers and metasurfaces.
Ramachandran has received several awards in regards to his research on exotic beams in fibers. He was most recently named a Vannevar Bush Faculty Fellowship in 2019, which is the most prestigious award for basic research given by the US Department of Defense. Ramachandran is using his fellowship to explore light-matter interactions with twisted light beams. His groundbreaking work has also been covered in various publications such as Science, Nature Communications and Optica.