Strengthening the Growth of Indian Defence by Harnessing Nanotechnology - A Prospective

Nano-networking is truly interdisciplinary and emerging field including nanotechnology, biotechnology, and ICT. It is a developing research area which consists of identifying, modeling, analyzing and organizing communication protocols between devices in Nanoscale environments. The main goal is to explore beyond the existing capabilities of Nanodevices by cooperating and sharing information between them. Since conventional communication models are not appropriate to represent Nanonetworks, it is necessary to introduce new communication paradigm in the form of suitable protocols and network architectures. Nanotechnology could greatly improve some of the existing technologies and thus create new operational opportunities or, at least, help the military forces to strengthen themselves in the battlefield. The paper presents a brief overview of nanotechnology applications in defence sector and the challenges towards realization of protocols for Nanocommunication. The research is going forward and one can expect more protection rather than damage in the domain of ‘Nano-age’.Defence Science Journal, 2013, 63(1), pp.46-52, DOI:http://dx.doi.org/10.14429/dsj.63.376

Subwavelength Engineering of Silicon Photonic Waveguides

The dissertation demonstrates subwavelength engineering of silicon photonic waveguides in the form of two different structures or avenues: (i) a novel ultra-low mode area v-groove waveguide to enhance light-matter interaction; and (ii) a nanoscale sidewall crystalline grating performed as physical unclonable function to achieve hardware and information security. With the advancement of modern technology and modern supply chain throughout the globe, silicon photonics is set to lead the global semiconductor foundries, thanks to its abundance in nature and a mature and well-established industry. Since, the silicon waveguide is the heart of silicon photonics, it can be considered as the core building block of modern integrated photonic systems. Subwavelength structuring of silicon waveguides shows immense promise in a variety of field of study, such as, tailoring electromagnetic near fields, enhancing light-matter interactions, engineering anisotropy and effective medium effects, modal and dispersion engineering, nanoscale sensitivity etc. In this work, we are going to exploit the boundary conditions of modern silicon photonics through subwavelength engineering by means of novel ultra-low mode area v-groove waveguide to answer long-lasting challenges, such as, fabrication of such sophisticated structure while ensuring efficient coupling of light between dissimilar modes. Moreover, physical unclonable function derived from our nanoscale sidewall crystalline gratings should give us a fast and reliable optical security solution with improved information density. This research should enable new avenues of subwavelength engineered silicon photonic waveguide and answer to many unsolved questions of silicon photonics foundries

Nano-scale reservoir computing

This work describes preliminary steps towards nano-scale reservoir computing using quantum dots. Our research has focused on the development of an accumulator-based sensing system that reacts to changes in the environment, as well as the development of a software simulation. The investigated systems generate nonlinear responses to inputs that make them suitable for a physical implementation of a neural network. This development will enable miniaturisation of the neurons to the molecular level, leading to a range of applications including monitoring of changes in materials or structures. The system is based around the optical properties of quantum dots. The paper will report on experimental work on systems using Cadmium Selenide (CdSe) quantum dots and on the various methods to render the systems sensitive to pH, redox potential or specific ion concentration. Once the quantum dot-based systems are rendered sensitive to these triggers they can provide a distributed array that can monitor and transmit information on changes within the material.Comment: 8 pages, 9 figures, accepted for publication in Nano Communication Networks, http://www.journals.elsevier.com/nano-communication-networks/. An earlier version was presented at the 3rd IEEE International Workshop on Molecular and Nanoscale Communications (IEEE MoNaCom 2013

Genetically Synthesized Supergain Broadband Wire-Bundle Antenna

High-gain antennas are essential hardware devices, powering numerous daily applications, including distant point-to-point communications, safety radars, and many others. While a common approach to elevate gain is to enlarge an antenna aperture, highly resonant subwavelength structures can potentially grant high gain performances. The Chu-Harrington limit is a standard criterion to assess electrically small structures and those surpassing it are called superdirective. Supergain is obtained in a case when internal losses are mitigated, and an antenna is matched to radiation, though typically in a very narrow frequency band. Here we develop a concept of a spectrally overlapping resonant cascading, where tailored multipole hierarchy grants both high gain and sufficient operational bandwidth. Our architecture is based on a near-field coupled wire bundle. Genetic optimization, constraining both gain and bandwidth, is applied on a 24-dimensional space and predicts 8.81 dBi realized gain within a half-wavelength in a cube volume. The experimental gain is 6.15 with 13% fractional bandwidth. Small wire bundle structures are rather attractive for designing superscattering and superdirective structures, as they have a sufficient number of degrees of freedom to perform an optimization, and, at the same time rely on simple fabrication-tolerant layouts, based on low-loss materials. The developed approach can be applied to low-frequency (e.g., kHz-MHz) applications, where miniaturization of wireless devices is highly demanded

Excellentia Eminentia Effectio

"In these pages you will learn about the fascinating research endeavors that each of our faculty members is undertaking. We have divided their research into the broad categories of health, sustainability, information, and systems. While we recognize the imperfect nature of categorizing research that, by its very nature may be interdisciplinary or transdisciplinary, we nonetheless believe it will be helpful as a way to see the depth and breadth of our research endeavors within each grouping. As you read the profiles on these pages, I know you will begin to appreciate that, taken as a whole, the research spectrum at Columbia Engineering is exceptional and that, as our professors go about their work, they are at the cusp of making breakthroughs that will have a major impact on the way we live our lives today and tomorrow.

Stochastic Memory Devices for Security and Computing

With the widespread use of mobile computing and internet of things, secured communication and chip authentication have become extremely important. Hardware-based security concepts generally provide the best performance in terms of a good standard of security, low power consumption, and large-area density. In these concepts, the stochastic properties of nanoscale devices, such as the physical and geometrical variations of the process, are harnessed for true random number generators (TRNGs) and physical unclonable functions (PUFs). Emerging memory devices, such as resistive-switching memory (RRAM), phase-change memory (PCM), and spin-transfer torque magnetic memory (STT-MRAM), rely on a unique combination of physical mechanisms for transport and switching, thus appear to be an ideal source of entropy for TRNGs and PUFs. An overview of stochastic phenomena in memory devices and their use for developing security and computing primitives is provided. First, a broad classification of methods to generate true random numbers via the stochastic properties of nanoscale devices is presented. Then, practical implementations of stochastic TRNGs, such as hardware security and stochastic computing, are shown. Finally, future challenges to stochastic memory development are discussed