Title: OpticalPulse Propagation and Direct Observation of Superluminality in DifferentDispersive Media
Speaker: Aminul I.Talukder
Department of Physics,University of Dhaka
Place: Room 201, Teaching Building 12, Yuquan Campus
Time: 15:00-16:00, Dec. 14th, Friday
Abstract
The propagation of optical pulses has beeninvestigated in different dispersive media. A transition from the Superluminalto subluminal of the propagation velocity is observed through a resonantlyabsorbing medium when the propagation distance is changed from a short to longrange. The propagation velocity is described within the framework of net groupand reshaping delays, even the medium causes a great deal of deformation in thetransmitted pulse. This has been confirmed for arbitrary shape of pulses throughdifferent types of absorptionless dispersive media such as angularly dispersiveone, photonic crystal fiber, etc. However, in the case of phase modulatedchirping pulses in a resonant absorber, the propagation velocity is stronglyinfluenced by the reshaping delay. Direct observation of superluminality orfast light has been confirmed from a series of experiments of pulse propagationthrough a fiber ring resonator within its negative group delay limit. It isobserved that the superluminal propagation of pulse peak is an analyticcontinuation over time of the earlier portion of the input pulse envelope.
Short Biography
Aminul IslamTalukder is a Professor of Physics at Dhaka University. He received his Ph.D.from Shizuoka University, Japan in 2001. Prof. Talukder’s research interests include superluminal light: measurementand it’s generalization in terms of group velocity, laser spectroscopy such asRaman and LIBS, nanoparticle fabrication using laser ablation technique,etc. He has published about 40 researchpapers, 1 book chapter and about 20 presentations/talks at internationalconferences, on topics such as superluminal pulse propagation, Ramanspectroscopy, laser induced breakdown spectroscopy, fabrication of metallicnanoparticles using laser ablation technique, etc. He has received RazzaqShamsun research award (for best research in Bangladesh) from Dhaka University.He was awarded with 3 postdoctoral fellowships; one from CommonwealthScholarship Commission during 2009-2010 at ORC, University of Southampton, UKand two other from JSPS (Japan Society for the Promotion of Science) during2003-2005 and 2012-2013 at Shizuoka University, Japan. He was the regularassociate of Abdus Salam International Center for Theoretical Physics (ICTP)during 2006-2012.
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