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Generation and detection of tunable orbital angular momentum in polarization-maintaining optical fiber

Event Details

Event Dates: 

Wednesday, September 6, 2017 - 4:00pm

Seminar Location: 

  • Duane Physics Room G1B20

Speaker Name(s): 

Juliet Gopinath

Speaker Affiliation(s): 

University of Colorado, Boulder
Seminar Type/Subject

Scientific Seminar Type: 

  • Physics Department Colloquium

Event Details & Abstract: 

In the past few years, twisted light, or light with orbital angular momentum (OAM) has captured interest a diverse array of applications.   It can be used to drive micromachines and in biophotonics, OAM is used in microscopy to achieve resolution orders of magnitude better than the diffraction limit. In astronomy, the OAM of light from distant stars carries information about the inhomogeneity of the interstellar medium and the shape of black holes.  In quantum information science, OAM states can be entangled, which leads to surprising demonstrations of quantum mechanics and potentially new computational possibilities. OAM-enabled communications, of all the applications, has received the majority of the attention due to the potential increase in fiber optic bandwidth that would be realized in a move from binary to a classical or quantum mechanical-vast parameter space per photon provided by the integer OAM states.

To date, specialty fiber has been used to carry OAM.   In this talk, I will describe new methods for generating OAM light in commercially available polarization maintaining optical fiber.   By adding up two higher order modes, generation of tunable OAM can be demonstrated.  In addition, I will discuss a new quantitative detection method for light with OAM and extensions of the technique.  Finally, I will present a method to control independently, both the OAM and the spatial beam profile.

Biography: Juliet Gopinath is an Associate Professor of Electrical, Computer and Energy Engineering at the University of Colorado Boulder.   She received her B.S. degree in Electrical Engineering from the University of Minnesota and her M.S. and Ph.D. degrees at MIT.   She worked at MIT Lincoln Laboratory from 2005 to 2009 on topics including cryogenic Yb:YAG lasers, beam combining, and mode-locked diode lasers.  Since 2009, she has run a group focused on optical devices and lasers at CU Boulder.  Her current research interests include ultrafast lasers, nonlinear optics, mid-infrared materials, spectroscopy, orbital angular momentum and adaptive optical devices.   She is the recipient of an Air Force Young Investigator Award (2010), R & D 100 Award (2012), an NSF CAREER award (2016), the CU Provost Achievement Award (2016) and is an Associate Editor for IEEE Photonics Journal.