Seminar: "Generation and modulation of optical
vortices with liquid crystal technology" by Prof. Yan-qing Lu
Friday, August 22, 2014 11:00 AM to 12:00 PM
CREOL Room 103
CREOL Room 103
Prof. Yan-qing Lu
College of Engineering and Applied Sciences, Nanjing
University, China
Abstract:
We present a technique for producing tunable optical
vortices and other structured wavefronts by using liquid crystal (LC)
photo-patterning technology. To write patterned alignment structures in to LC
cells, a home-made micro-lithography system with a digital micro-mirror device
(DMD) as dynamic mask forms arbitrary micro-images on photo-alignment layers
and further guides the LC molecule orientations. Arbitrary fine
photo-patterning fork gratings, polarization fork gratings, q-plates are
fabricated. The related wavefront transformation properties are studied. Clear
optical vortices with designed topological charges are obtained in different
wavelengths. When a voltage is applied on the cell, index re-distribution is
induced due to the realignment of LC molecules; and then the optical vortices
become tunable. In addition, some recent results on LC tunable Airy beams,
vector beams are also introduced.
Biography:
Prof. Yan-qing Lu received both his BS and Ph.D.
degrees from Nanjing University, China, in 1991 and 1996 respectively. He has
five-year experiences in US and China telecomm industries. He designed and
developed a serial of liquid crystal based fiber-optic devices with his
colleagues, which include variable optical attenuators, variable Mux/Demux, DWDM
wavelength blocker etc. He is currently a Professor at the College of
Engineering and Applied Sciences, Nanjing University. His research interests
include liquid crystal photonics, nonlinear optics and fiber optics. He is the
author or co-author of ~130 peer-reviewed papers with over 1600 ISI citations.
He also holds more than 40 domestic or international patents or pending
patents. He currently serves as a deputy editor of Optical Materials Express.
He was a visiting research scientist in Prof. S. T. Wu’s group in CREOL from
2003 to 2005.
For more information:
Prof. Shin-Tson Wu, 407-823-4763
SID Student Chapter: Daming Xu
IEEE Photonics Student Chapter: Zhenyue Luo
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