Light That Twists Inside Fibers

Date: 10:00am, December 1, 2017
Location: Davis Auditorium
Speaker: Siddharth Ramachandran ECE Department & Photonics Center, Boston University
Video Link

Abstract:  In the last decade, some of the most extensively studied complex light beams are optical vortices, which possess phase or polarization singularities and can carry orbital angular momentum. These beams resemble the emission patterns of single molecule dipoles, and represent a potentially infinite set of eigenstates that can be constructed with light. Their use has been demonstrated in, or proposed for, several applications such as higher-dimensional quantum encryption, single-molecule spectroscopy, exoplanet detection, information capacity scaling, nano-scale imaging and laser wakefield acceleration.

A recently developed optical fiber waveguide, designed by exploiting spin-orbit coupling interactions commonly encountered in electronic systems, has enabled the stable generation and propagation of optical vortices in fibers for distances of up to kilometres. Since fibers are well known for their ability to offer nonlinear and dispersive tailoring of light, this additionally opens the door to studying and exploiting nonlinear phenomena with such beams. This talk will discuss recent results and intriguing possibilities enabled by fiber propagation of beams that have long been considered interesting, but hitherto unstable in nature.

Biography: 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.

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