Space: the less explored dimension of light
08 Nov, 2017 (Wed)
11:00 am
Room 603, Chow Yei Ching Building

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Prof. Siddharth Ramachandran
ECE Department & Photonics Center, Boston University, Boston, MA, USA


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Siddharth Ramachandran

Prof. Siddharth Ramachandran

When we think of a beam of light, we generally think of a spot; or a beam that travels in a straight line with a Gaussian shape. On the other hand, higher-order eigenstates of light manifest in an infinite-dimensional set of spatially complex beam patterns possessing phase- and/or polarisation-singularities. Such beams have long been known to possess several intriguing characteristics such as enhanced propagation stability, phase fronts that evolve helically rather than in a straight line (hence beams that carry orbital-angular-momentum), and the ability to self-heal past obstructions, to name a few. These unique characteristics make them attractive for applications as diverse as super-resolution microscopy, deep-tissue imaging, DNA sorting, classical and quantum communications, remote sensing and directed-energy defence strategies.

These favourable attributes notwithstanding, higher order modes of light have been traditionally perceived to be inherently unstable in guided media such as optical fibers. Recent work has upended this perception, and today, suitably designed optical fibers can transmit such exotic states of light over lengths as long as 10 km. Since fibers are well known for their ability to offer nonlinear and dispersive tailoring, the systematic and controllable study of nonlinear interactions of higher order modes is now feasible. This talk will discuss recent results and applications enabled by fiber propagation of beams that have long been considered interesting and useful, but hitherto unstable in nature.


Biography of the speaker:

Dr. Siddharth Ramachandran obtained his Ph.D. in Electrical Engineering from the University of Illinois, Urbana-Champaign, in 1998. Thereafter, he joined Bell Laboratories as a Member of Technical Staff and subsequently continued with its spin-off, OFS Laboratories. After a decade in industry, Dr. Ramachandran moved back to academics in 2010, and is now a Professor in the Department of Electrical Engineering at Boston University.

Prof. Ramachandran’s research focuses on the optical physics of guided waves. He has authored over 250 refereed journal and conference publications, more than 70 invited talks, plenary or keynote lectures and tutorials, 3 book-chapters, edited one book, and has been granted 39 patents. For his contributions in the field of fiber-optics, he was named a Distinguished Member of Technical Staff at OFS Labs in 2003, a fellow of the Optical Society (OSA) in 2010, an IEEE Distinguished Lecturer for 2013-2015, and a Distinguished Visiting Fellow of the UK Royal Society of Engineering in 2016. He serves as a topical editor for Optica in addition to having served or serving on numerous conference and advisory committees in the field of optics and applied physics, including, recently, as general chair for CLEO-2017.


Prof. K.Y. Wong

Most seminars are open to the general public, free of charge, unless otherwise stated. Registration is not required. Arrangement for car parking facilities on campus please contact us for details.

For enquiries, please contact:
Department of Electrical and Electronic Engineering,
Room 601, Chow Yei Ching Building,
Pokfulam Road, Hong Kong
Tel: (852) 3917 7093