Applied Physics Seminar (Thursday, 5 June - 15:00 - Euler lecture hall)

[Crespo Maria Liz]

Thursday, 5 June at 15:00 hrs.
Euler lecture hall, ICTP Leonardo Building

TITLE:
All-Optical Ultrafast Switching and Computing with Photochromic Proteins,
Organic Molecules and Silicon Microring Resonators:
Integrating Technologies to meet Present Challenges

Professor Sukhdev Roy
Department of Physics and Computer Science
DAYALBAGH EDUCATIONAL INSTITUTE
Dayalbagh, Agra 282 110 India
Email : sukhdevroy at dei.ac.in

ABSTRACT:
Light sustains life on earth and is one of the most important signals
providing information to biological systems. Diverse systems such as
plants, seaweeds, and photosynthesizing bacteria absorb ambient light and
convert it into their life energy. In addition to human vision, light
controls movement, growth, differentiation, development, circadian clock
and a host of gene-expression responses in diverse organisms, from the
simplest unicellular microorganisms through higher plants and animals.
During the past decade, there has been extraordinary progress in
identifying and characterizing ultrasensitive natural photoreceptor
proteins in a broad range of organisms to understand the signal
transduction pathways and to get an insight into their multifunctional
response. The prospect of using their efficient nonlinear optical response
optimized over centuries of evolution, for photonic applications, is
extremely fascinating. Moreover, with the powerful capabilities of nano
and biotechnologies, their photo-response can also be tailored to meet
desired specifications.
The talk would focus on some of our recent experimental and theoretical
results on low-power all-optical switching in unique natural photoreceptor
molecules, namely, archael rhodopsin proteins, such as, bacteriorhodopsin
(BR), pharaonis phoborhodopsin (a sensory rhodopsin II), proteorhodopsin;
plant based blue light sensitive LOV2 phototropin, photoactive yellow
protein (PYP) and chlorophyll-A, based on excited-state absorption. The
performance will be compared with other organic molecules such as
fullerenes, organic dyes, organometallics-Cu-phthalocyanines and
graphene-oxide.
Integrating photochromic proteins with micro-nanostructures leads to
enhanced functionality. Experimental and theoretical results of
all-optical switching of a near-IR signal in a 2 x 2 optically controlled
microresonator using either (i) BR-coated ultrahigh-Q silica
microresonator coupled between two single-mode optical fibers or (ii)
silicon microring resonators coupled to integrated-optical waveguides,
will also be presented. It will be shown that using this versatile
configuration as a template, a wide range of all-optical ultrafast
Boolean, reversible and reconfigurable computing circuits can be designed
that include, logic gates, half-full adders-subtractors, counters,
multiplexer (MUX)/de-multiplexers (DE-MUXs), decoder-encoder, comparator,
flip-flops, RAM and arithmetic and logic unit (ALU); conservative and
reversible Fredkin, Toffoli, Feynman and Peres gates; and reconfigurable
logic circuits.
The talk would highlight (i) the emergence of natural photoreceptors as a
new class of photonic materials for information processing, solar energy
conversion and sensing, (ii) the importance of integrating technologies,
i.e., Nano-Bio-Photonics to meet present challenges, and (iii) the
prospects for ultrafast optical information processing.


Brief Biography of Professor Sukhdev Roy
----------------------------------------
Sukhdev Roy received B.Sc. (Honors) in Physics from Delhi University and
M.Sc. Physics with specialization in Electronic Science from Dayalbagh
Educational Institute, Agra, India in 1986 and 1988, respectively. He
obtained his PhD. in Physics from the Indian Institute of Technology
Delhi, in 1993 and joined the Department of Physics and Computer Science,
Dayalbagh Educational Institute, Agra, India, where he is at present a
Professor. He has been a Visiting Scientist at Harvard University,
University of Waterloo, Osaka University, Hokkaido University, City
University, London, Queen Mary University of London, Tata Institute of
Fundamental Research, Mumbai and the Indian Institute of Science,
Bangalore. He is an Associate of the Abdus Salam International Centre for
Theoretical Physics, Trieste, Italy. He has won a number of awards and
fellowships that include the JSPS Invitation Fellowship, Japan, 2004, IETE
Biennial Emerging Opto-electronic Technologies Award, 2012, 1st IETE B.B.
Sen Memorial Award, 2007, Hari Om Ashram Prerit H.C. Shah Research
Endowment Prize by Sardar Patel University, 2006, AICTE Career Award for
Young Teachers, 2001 and many best paper awards. He was the Guest Editor
of the March 2011 Special Issue of IET Circuits, Devices and Systems
Journal on Optical Computing. He is a Fellow of the Indian National
Academy of Engineering and Institution of Electronics and
Telecommunication Engineers (IETE), India and a Senior Member of IEEE
(USA).
His current research interests are in low-power nonlinear optics, quantum
photonics, and nano-photonics that includes organic, silicon and
bio-photonics, for ultrafast all-optical information processing, energy
conversion and sensing.