Day 3 :
The American University in Cairo, Egypt
Keynote: On-chip plasmonic modulator
Time : 09:30-10:00
M A Swillam is Received his Ph. D from McMaster University, Hamilton, Canada in 2008. After graduation he worked as post-doctoral fellow in the same group. In October 2009, he joined the photonic group and the institute of optical sciences at the University of Toronto where he works as a research fellow. In September 2011, he joined the Department of Physics, the American university in Cairo (AUC). He authored more than 175 technical papers in highly ranked journals and conferences. He also hold 2 patents, a book, and book chapter in these areas. Dr. Swillam is an editor in few international Journals He is also member of the editorial board of many conferences He is also a senior member of the IEEE Photonic society since 2010. He is the founder and the advisor of the optical society of America and SPIE chapters at the AUC and the vice president of the Egyptian Unit.
Surface plasmon polaritons SPPs are electromagnetic waves generated at the interface between a dielectric and a high electron density material such as metals. The field of manipulating and dealing with such distinguished electromagnetic waves is known as the field of plasmonics. The most significant properties of plasmonics are the ability of confining the electromagnetic energy to beyond the classical diffraction limit, and the enhancement of the electromagnetic fields as for example in the metaldielectric-metal slot. So, plasmonics offer the miniaturization of photonic components to nano-scales that were not possible to achieve using the conventional silicon photonics platform. Since plasmonic components are in the nano-scale, then, plasmonics which enable the integration of the photonic and electronic components on the same chip since they have comparable sizes. Distinct applications based on plasmonics have been successfully produced and studied such as sensors1-3, filters, multiplexers, interferometers, and modulators. The modulator is one of the most significant components in telecommunication devices. Since silicon weak nonlinear electro-optic effects, its modulation ability is very poor. However, plasmonics have shown the ability to integrate high nonlinear electro-optic polymers EOPs with plasmonic components to produce high performance plasmonic modulators4-8. Such modulators have the advantages of high speed operation and minimized device size. In this paper, we introduce an on-chip plasmonic modulator, which is characterized by its high modulation depth, low power consumption, and small footprint. The modulator is based on the ring resonator mechanism the structure is built from a stack of five layers above a SiO2 substrate. The layers are built as Si-EOP-metal-EOP-Si. Upon applying a small voltage across the EOP layers, the EOP changes its refractive index, so the plasmonic mode changes its effective index value, this results in a change of the resonant wavelength/frequency in the ring resonator. Fig.1 shows the shift of the resonant wavelength due to an application of voltage of only 1.3V. This wavelength shift can be understood as a change in level of the transmitted power, thereby can be viewed as optical modulation..
S N Bose National Centre for Basic Sciences, India
Time : 10:00-10:30
P Singha Deo did his PhD in 1996 and has remained associated with research and teaching in physics in premier institutions and universities of abroad and in India. He has published more than 50 papers in international journals. He is a Professor at S N Bose Centre, Kolkata since 1999 and successfully guided several PhD theses. He has worked on various issues and problems in mesoscopic physics and correlated systems. Some of his current research topics include quantum devices, quantum capacitance, bosonization in higher dimensions, quantum mechanical scattering phase shift in low dimensions, etc.
Scattering phase shift of an electron in quasi-one-dimensional systems can now be experimentally measured. The experiment has accentuated many theoretical problems. In this study we have addressed these problems using the concept of burgers circuit. In case of scattering in quasi one dimension, the contour PDABQCRS in the first Reimann surface can have subloops like ABQC in fig. Such a sub-loop is very new and novel to quasi one dimension and does not occur in one, two or three dimensions. Observation of such a subloop helps us to prove some results. Whether partial density of states (PDOS) can be negative is still an open problem. On applying the concept of burgers circuit on a closed subloop we can prove its negativity. The proof does not depend on explicit calculations for specific models but uses the topological properties of subloops and is general. Realistic potentials have been shown to generate such subloops and also the fact that such subloops are consistent with the burgers circuit which suggests that such subloops can occur in a large class of mesoscopic systems. It has been also argued that such negative PDOS can have several physical consequences including a mechanism for electron-electron attraction. We can also prove that semiclassical Friedel sum rule can become exact in a purely quantum regime. This can help us to experimentally determine the density of states and hence mesoscopic thermodynamic and transport properties without knowing the exact potential or impurity configuration inside the sample.