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Guest Lecture

1. 16th April 2021 (Friday) at 06.30 pm, Venue: Zoom

Prof. Gautam Vemuri
Department of Physics
Indiana University Purdue University Indianapolis (IUPUI).

Topic: Parity-time symmetry in time-delay coupled semiconductor lasers


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Read Abstract

A semiconductor laser with optical feedback is a paradigm for studying nonlinear dynamics in delayed feedback systems and has been intensely investigated in recent years. At a fundamental level, these investigations are an ideal test bed for laboratory studies of time-delayed systems. At an applied level, some of the dynamical behaviors that arise in these systems have been exploited for cryptography, and random number generation, among others. In this talk, I will give an overview of the dynamical behaviors that arise in semiconductor lasers due to various types of optical feedback, and experimental strategies for controlling the laser intensity and optical frequency dynamics. Time permitting, I will conclude with recent work on laboratory realizations of effective non-Hermitian Hamiltonians in time-delay coupled semiconductor lasers.

About the Speaker

Gautam VemuriProf. Gautam Vemuri
Gautam Vemuri received the Ph.D. (Physics) in 1990 from Georgia Institute of Technology, and after a postdoctoral stint at JILA, has been on the Physics faculty at Indiana University Purdue University Indianapolis (IUPUI) since 1992. He is currently a Professor of Physics, and from 2002-2009 served as the Chair of the Department. His research interests are in laser physics and nonlinear optics, with special emphasis on stochastic and nonlinear dynamical behaviors of optical systems, topics on which he has published about 90 journal articles. He served on the editorial board of Optics Communications from 1998 to 2015, and was a founding member of the American Physical Society’s Prairie Section.

2. 5th May 2021 (Wednesday) at 03.30 pm, Venue: MS Teams Meeting

Dr. Parthiban Ramasamy
Erich Schmid Institute of Materials Science
Leoben, Austria.

Topic: Bulk Metallic Glasses for Magnetic Applications - An Advancement in Material Science

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Fe-based bulk metallic glasses (BMGs) have gained considerable interest due to their excellent soft magnetic properties with high saturation magnetization, high electrical resistivity, very good corrosion resistance, low materials cost, extremely high mechanical strength, and hardness. In spite of having excellent magnetic properties, Fe-based BMGs are not used as engineering materials in service, so far. The major obstacle is their inherent brittleness under mechanical loading, once a crack is developed the material fails catastrophically. Owing to the ever-growing industrial demand for materials with outstanding properties, aside from exploring new alloy compositions, it is pertinent to understand why or why-not the existing system work and how to improve their properties. In this work I have attempted to understand the basics behind improving the room temperature plastic deformability in Fe36Co36B19.2Si4.8Nb4 and Fe74Mo4P10C7.5B2.5Si2 ferromagnetic BMGs. Addition of small at.% Ga proved to be a viable solution to improve the plastic deformability in the ferromagnetic Fe-based metallic glasses without compromising on thermal and magnetic properties of the glass. I have also attempted to gain basic knowledge in casting the Fe-based BMG on an industrial scale. My effort was tremendously successful; I was able to produce fully amorphous complex-shaped samples with the excellent surface finish.

About the Speaker

Dr. Parthiban Ramasamy
Dr. Parthiban Ramasamy did his PhD. from the Technical University Dresden, Germany in the Faculty of Materials Science and Engineering. He was a Scientific Researcher at Leibniz Institute for Solid State and Materials Research – IFW, Dresden, Germany. Presently he is working at Erich Schmid Institute of Materials Science of Austrian Academy of Sciences, Leoben, Austria. Dr Parthiban was the recipient of the ‘DAAD (German Academic Exchange Service)’ fellowship during his Masters and ‘Marie Curie Sklodowska’ Fellowship to carry out his PhD. Dr Ramasamy’s research interests are Soft ferromagnetic bulk metallic glasses for magnetic and structural applications, Ti- and Mg-Ca based metallic glasses for biomedical applications, Alloy designing and improving the mechanical properties of bulk metallic glasses, Thermomechanical treatment and structural evaluation in bulk metallic glasses. Dr Parthiban has published more than 20 journal articles and is presently working on two projects based on Optimization of Soft Ferromagnetic Powders for Telecommunication and Selective Laser Melting Technology for The Preparation of High-Performance CuZr Matrix Amorphous Composites.

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