CREOL COLLOQUIUM SERIES: Dr. Siddharth Ramachandran, Boston University

Friday, October 13, 2023 noon to 1 p.m.

Title: Long-lived Photons in Forbidden States: the influence of light’s topology on its propagation characteristics

Abstract: Since the elucidation of total internal reflection by Colladon, Babinet and Tyndall over 150 years ago, bound states of light have been the primary means to transport light, whether on a chip or in optical fibers. We show that light carrying sufficiently high orbital angular momentum can create a centrifugal barrier for itself, thereby enabling guidance even in a regime where a mode is normally considered “cutoff,” that is, in a regime where bound states of light are conventionally forbidden. We will discuss how this discovery, which has parallels with why binary stars don’t collapse into each other due to gravity, has applications in diverse areas, including classical and quantum communications and computing with high dimensionality, power scaling of fiber lasers by mitigating nonlinearities, and nonlinear optics with greater degrees of freedom.

About the Speaker: Dr. Siddharth Ramachandran started his scientific career at Bell Labs, and after a decade in industrial research labs, returned to academia, where he is currently a Distinguished Professor of Engineering at Boston University. For his contributions to the understanding and development of lightwave devices comprising spatial, vectorial and topological complexity, he has been named a Distinguished Member of Technical Staff at OFS (2003), a fellow of Optica (2010), IEEE (2019), SPIE (2019) and APS (2022), an IEEE Distinguished Lecturer (2013-2015, and a Vannevar Bush Faculty Fellow (2019). He serves the optics and photonics community in several capacities, including, currently, as a deputy editor for Optica.

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