Siddharth Ramachandran, Boston University: The Physics and Applications of Topologically Complex Light

When we think of a laser beam, we visualize it illuminating a spot, with a roughly Gaussian intensity distribution. But this is just the ground state solution of the wave equation that describes the propagation dynamics of light. In analogy with electrons in atomic or molecular orbitals, higher order eigenstates of light can be spatially, topologically and vectorially complex in interesting ways that influence their linear and nonlinear dynamics. Upon confinement, either by focusing or by guiding them in fibers, they can also experience spin-orbit interactions that fundamentally alter their nonlinear behaviour. This talk will describe the physics of propagation of these states, especially in fibers that enhance spin-orbit interactions. We will then illustrate how their unique properties have led to applications in disparate areas such as energy-efficient internet architectures, higher capacity quantum computing, super-resolution microscopy as well as new modalities of sensing.