This article is an autobiography or has been extensively edited by the subject or by someone connected to the subject.(May 2017) |
Prof. Ravindra Kumar | |
---|---|
Born | 15 February 1960 |
Nationality | Indian |
Alma mater | Indian Institute of Technology (IIT) Delhi, Indian Institute of Technology (IIT) Kharagpur |
Known for | Research work on Photonic Crystal Based Nanophotonic Devices including Zero Index Metamaterials for telecom and sensing applications. |
Scientific career | |
Thesis | A Study of the Propagation Characteristics of Rectangular Core Optical Waveguides and Devices (1989) |
Website | http://rksinha.in/ |
Prof. R K Sinha (born 15 February 1960) is the Vice Chancellor of Gautam Buddha University, Greater Noida, Gautam Budh Nagar Under UP Government. He was the director of the CSIR-Central Scientific Instruments Organisation (CSIR-CSIO) Sector-30C, Chandigarh-160 030, India. [1] [2] He has been a Professor - Applied Physics, Dean-Academic [UG] & Chief Coordinator: TIFAC-Center of Relevance and Excellence in Fiber Optics and Optical Communication, Mission REACH Program, Technology Vision-2020, Govt. of India Delhi Technological University (formerly Delhi College of Engineering, University of Delhi) Bawana Road, Delhi-110042, India. [3]
Prof. Sinha graduated with masters in physics (M.Sc Physics) from Indian Institute of Technology (IIT) Kharagpur in 1984 and moved to Indian Institute of Technology (IIT) Delhi from where he secured a PhD in 1989-90. [4] Topic of his PhD thesis is A Study of the Propagation Characteristics of Rectangular Core Optical Waveguides and Devices under the guidance of Prof Arun Kumar and Prof B.P. Pal in Optical wave guide group headed by Prof. Ajoy Ghatak during the period of 1984-1989.
He worked at Osaka University for foreign studies, Osaka and Kobe University in Japan as Japanese government scholar during the period October 1989 - March 1991. Further during April 1991 - December 1992 he has worked as Research Associate in Electrical Communication Engineering Department of Indian Institute of Science (IISc), Bangalore.
He joined as lecturer at Birla Institute of Technology and Science (BITS) Pilani during January 1992 - September 1994.Thereafter he was assistant professor at Regional Engineering College, now known as National Institute of Technology (NIT) at Hamirpur (H.P.), India during October 17, 1994 - December 30, 1998. Then he joined as assistant professor at Delhi College of Engineering-DCE (Faculty of Technology, University of Delhi) during December 31, 1998 to October 17, 2002 .
He was Dean (Industrial Research & Development) at DCE/DTU during August 7, 2008 to August 31, 2010 and Head of Department of Applied Physics Department and Dean (academic-UG) during January 2015 to June 2015 at Delhi Technological University.
He was a Chief Coordinator: TIFAC-Center of Relevance & Excellence (CORE) in Fiber Optics & Optical Communication at Delhi College of Engineering” under the program “Mission Reach”, Technology Vision 2020, Technology Information Forecasting and Assessment Council, Department of Science & Technology, Govt. of India since its inception in year 2005.
He has served as a Director, CSIR-Central Scientific Instruments Organisation (CSIO) Chandigarh since July 2, 2015 to February 2020. He has also served as Director, CSIR-Central Electronics Engineering Research Institute (CEERI), Pilani during November 6, 2015 to March 8, 2016 and Director CSIR-Institute of Microbial Technology (IMTECH), Chandigarh since April 11, 2016 to January 22, 2017 as additional charge. His major research area is Fiber Optics and Photonics and he is currently working on Nano-photonic Devices for Telecom and Sensing Applications.His recent book on Zero Index Metamterials is published in April 2021 (https://www.google.co.in/books/edition/Zero_Index_Metamaterials/h_QkEAAAQBAJ?hl=en&gbpv=1&printsec=frontcover ). [5] He has also published a review paper on Supercontinuum Generation using soft glass specialty optical fiber. [6] He is recipient of Research Excellence Award of DTU in 2021 & 2022, Gold Skoch Award for development of defense technology in 2020, CSIR Technology Award 2018, Fulbright-Nehru Fellowship, Royal Academic Engineering Fellowship, Indo-Swiss Bilateral Research Fellowship, Japan Society for promotion of Science Fellowship, Japanese Govt. Scholarship, National Council of Taiwan Fellowship besides several visiting scientist assignment in several country. He is a fellow of International Society of Optics and Photonics (SPIE), Optical Society of India and IETE(India).
Dr. Sinha is a member of many boards and other organizations. Some of them are:
Successfully developed theory and experiments for characterization of telecom grade single mode optical fibers as well as elliptical core fibers for coherent optical communication from measurements of far field radiation patterns. This technique was extended for developing new methods for characterization of single mode integrated planar and rectangular core channel optical waveguides from far field measurements. [12] [13] This was followed by the development of coupled mode theory for design of 4x4 optical fiber and waveguide couplers and their applications in the design of optical homodyne receivers. [14] [15]
Development of analytical methods for dispersion compensation of light wave signals using differential time delay technique incorporating the effect of higher orders terms in propagation constant of modes in optical fiber for their application in higher rate of data transmission. [16] [17] Development of a scheme for bit delay correction for WDM based Optical Communication System. [18] Multiple Access techniques in Optical Fiber Communication systems leading to development of 3-D Optical Code sequences. Optical CDMA and Optical Turbo Codes and their performance evaluation in terms of SNR, BER and ISI in optical communication systems are published by me as author/co-author of leading journals of repute. [19] [20] [21] [22]
Development of coupled mode theory for Electron Waveguide and their application in the design of high speed Quantum Size Devices based on electron wave propagation in multiple quantum well semiconductors at Nano-scale was proposed and nano-electronic devices (Electron Waveguide Couplers, Switches and Filters) were designed with enhanced transmission characteristics. [23] [24] [25]
In addition to the above, most of his recent significant research contributions are:
Photonic Crystal based nanophotonic devices: Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics. Various new design of photonic crystal made of silicon on insulator (SOI) is proposed for design and development of photonic crystal based coupler, Y splitter, Dual band wavelength multiplexor and de-multiplexors. A new design of Super polarizer is also proposed and its degree of polarization and fabrication tolerance were also estimated. This was followed by the design of photonic crystal structure for slow light generation leading to formation of soliton at incredibly low power, design of Dense Wavelength Division Multiplexor (DWDM) and de-multiplexore for telecom application. [26] [27] [28] [29] [30] [31] [32] [33] [34]
Metamaterials and Negative refraction: A new structure of exhibiting negative refraction (called metamaterial) is designed, analyzed, fabricated and experimentally characterized. This was experimentally realized using V-shaped split ring resonator made up of two dimensional arrays of 50 nanometer thick gold on n-doped silicon substrate. It is shown that by changing the angular gap of V- shaped SRRs, it is possible to tune the electromagnetic parameters (such as dielectric permitivity, permeability and refractive index) and control the flow of light for design and development of metamaterial based optical switches and sensors at nano-scale. [35] [36]
In addition, left handed (metamaterials exhibiting negative refraction) metallo-dielectric photonic crystal exhibiting All Angle Negative Refraction for visible light is analyzed with detailed theoretical and numerical demonstration for the first time. On the same line another new design of left handed metamaterial structure is analyzed and proposed for generation of ultra violet light via second harmonic generation. Here, it is shown that negative index is achieved by excitation of Surface Plasmon Polariton waves operating in dispersion regime with anti parallel refracted wave vector and the Poynting vector. [37] [38] [39] [40] [41] [42]
Plasmonics & Plasmonic Bandgap Engineering: Surface Plasmon Polaritons (SPPs) are electromagnetic waves guided along metal dielectric interfaces resulting from the interaction of incident photon with that of collective electron oscillation in metals. SPPs have shorter wavelength than that of incident photons and hence provide strong spatial confinement with promising application in the design and development of sub nano-scale devices. A new concept of Plasmonic Band Gap engineering is highlighted and used for SPP propagation leading to formation of Plasmonic Waveguides. Several types of plasmonic waveguides exhibiting superior propagation characteristics were designed leading to proposal of a new design of Plasmonic Mach-Zhender Interferrometer (PMZI) sensor. It is shown that proposed PMZI has very high sensitivity of the order of 6000 nm/RIU, which has been effectively used for label free classification and detection of cancer cell. [43] [44] [45] [46] [47] [48] [49] [50] [51]
Field Emission characteristics of Carbon Nanotube (CNT) & Nano-Bio Sensors: CNTs were grown using Inconel and silicon substrates and their field emission characteristics have been studied with a view of their promising applications for next generation high performance flat panel devices. Later field emission with ultralow turn on voltage (of the order 0.1 volt/µm) from metal decorated CNTs have been obtained. A single-step method for synthesis and deposition of gold nanostructures was developed for fabrication of a highly sensitive and selective cholesterol nano-biosensor. Using electrochemical synthesis and assembly of gold nanostructures high performance electrochemical biosensor is fabricated which can be utilized for healthcare diagnostic applications. [52] [53] [54] [55]
Photonic Crystal Fiber (PCF) & Supercontinuum generation: Prof. Sinha developed several analytical and numerical techniques for studying light wave propagation characteristics through specially designed photonic crystal fibers and developed experimental techniques for their characterization which have become topic of various text and reference books these days and very well cited by research community. Application specific photonic crystal fibers like large mode area PCF and Triangular core PCF were also designed. Very recently, a new design of PCF called Triangular Core Graded Index PCF were designed and analyzed for ultra broad band ( i.e. 2-15 µm, so far highest range) supercontinuum spectrum in mid infrared region. [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74]
A photonic crystal is an optical nanostructure in which the refractive index changes periodically. This affects the propagation of light in the same way that the structure of natural crystals gives rise to X-ray diffraction and that the atomic lattices of semiconductors affect their conductivity of electrons. Photonic crystals occur in nature in the form of structural coloration and animal reflectors, and, as artificially produced, promise to be useful in a range of applications.
A metamaterial is any material engineered to have a property that is rarely observed in naturally occurring materials. They are made from assemblies of multiple elements fashioned from composite materials such as metals and plastics. These materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable of manipulating electromagnetic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials.
Photonic-crystal fiber (PCF) is a class of optical fiber based on the properties of photonic crystals. It was first explored in 1996 at University of Bath, UK. Because of its ability to confine light in hollow cores or with confinement characteristics not possible in conventional optical fiber, PCF is now finding applications in fiber-optic communications, fiber lasers, nonlinear devices, high-power transmission, highly sensitive gas sensors, and other areas. More specific categories of PCF include photonic-bandgap fiber, holey fiber, hole-assisted fiber, and Bragg fiber. Photonic crystal fibers may be considered a subgroup of a more general class of microstructured optical fibers, where light is guided by structural modifications, and not only by refractive index differences. These fibers can have hollow cores and be known as hollow-core fibers.
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light guides, and liquid waveguides.
An optical circulator is a three- or four-port optical device designed such that light entering any port exits from the next. This means that if light enters port 1 it is emitted from port 2, but if some of the emitted light is reflected back to the circulator, it does not come out of port 1 but instead exits from port 3. This is analogous to the operation of an electronic circulator. Fiber-optic circulators are used to separate optical signals that travel in opposite directions in an optical fiber, for example to achieve bi-directional transmission over a single fiber. Because of their high isolation of the input and reflected optical powers and their low insertion loss, optical circulators are widely used in advanced communication systems and fiber-optic sensor applications.
In optics, a supercontinuum is formed when a collection of nonlinear processes act together upon a pump beam in order to cause severe spectral broadening of the original pump beam, for example using a microstructured optical fiber. The result is a smooth spectral continuum. There is no consensus on how much broadening constitutes a supercontinuum; however researchers have published work claiming as little as 60 nm of broadening as a supercontinuum. There is also no agreement on the spectral flatness required to define the bandwidth of the source, with authors using anything from 5 dB to 40 dB or more. In addition the term supercontinuum itself did not gain widespread acceptance until this century, with many authors using alternative phrases to describe their continua during the 1970s, 1980s and 1990s.
Allan Dawson Boardman was a British physicist, known for his work on surface plasmons and guided wave optics, especially nonlinear waves, solitons, magneto-optics and negative refracting metamaterials. He was a theorist and numerical analyst in these areas, especially magneto-optics and metamaterials. In 2006 he was made a fellow of the Optical Society of America for his contributions in these fields and for "exemplary leadership and service to the optics community".
A subwavelength-diameter optical fibre is an optical fibre whose diameter is less than the wavelength of the light being propagated through it. An SDF usually consists of long thick parts at both ends, transition regions (tapers) where the fibre diameter gradually decreases down to the subwavelength value, and a subwavelength-diameter waist, which is the main acting part. Due to such a strong geometrical confinement, the guided electromagnetic field in an SDF is restricted to a single mode called fundamental.
A photonic metamaterial (PM), also known as an optical metamaterial, is a type of electromagnetic metamaterial, that interacts with light, covering terahertz (THz), infrared (IR) or visible wavelengths. The materials employ a periodic, cellular structure.
The history of metamaterials begins with artificial dielectrics in microwave engineering as it developed just after World War II. Yet, there are seminal explorations of artificial materials for manipulating electromagnetic waves at the end of the 19th century. Hence, the history of metamaterials is essentially a history of developing certain types of manufactured materials, which interact at radio frequency, microwave, and later optical frequencies.
Optofluidics is a research and technology area that combines the advantages of fluidics and optics. Applications of the technology include displays, biosensors, lab-on-chip devices, lenses, and molecular imaging tools and energy.
A plasmonic metamaterial is a metamaterial that uses surface plasmons to achieve optical properties not seen in nature. Plasmons are produced from the interaction of light with metal-dielectric materials. Under specific conditions, the incident light couples with the surface plasmons to create self-sustaining, propagating electromagnetic waves known as surface plasmon polaritons (SPPs). Once launched, the SPPs ripple along the metal-dielectric interface. Compared with the incident light, the SPPs can be much shorter in wavelength.
Ortwin Hess is a German-born theoretical physicist at Trinity College Dublin (Ireland) and Imperial College London (UK), working in condensed matter optics. Bridging condensed matter theory and quantum optics he specialises in quantum nanophotonics, plasmonics, metamaterials and semiconductor laser dynamics. Since the late 1980s he has been an author and coauthor of over 300 peer-reviewed articles, the most popular of which, called "'Trapped rainbow' storage of light in metamaterials", was cited more than 400 times. He pioneered active nanoplasmonics and metamaterials with quantum gain and in 2014 he introduced the "stopped-light lasing" principle as a novel route to cavity-free (nano-) lasing and localisation of amplified surface plasmon polaritons, giving him an h-index of 33.
Richard Magee Osgood Jr. was an American applied and pure physicist. He was Higgins Professor of Electrical Engineering and Applied Physics at Columbia University.
Plasmonics or nanoplasmonics refers to the generation, detection, and manipulation of signals at optical frequencies along metal-dielectric interfaces in the nanometer scale. Inspired by photonics, plasmonics follows the trend of miniaturizing optical devices, and finds applications in sensing, microscopy, optical communications, and bio-photonics.
Anurag Sharma is an Indian physicist and a professor at the department of physics of the Indian Institute of Technology Delhi. He is known for his pioneering researches on optoelectronics and optical communications and is an elected fellow of all the three major Indian science academies viz. Indian Academy of Sciences, Indian National Science Academy and National Academy of Sciences, India as well as Indian National Academy of Engineering. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Engineering Sciences in 1998.
Jonathan C. Knight, is a British physicist. He is the Pro Vice-Chancellor (Research) for the University of Bath where he has been Professor in the Department of Physics since 2000, and served as head of department. From 2005 to 2008, he was founding Director of the university's Centre for Photonics and Photonic Materials.
Spoof surface plasmons, also known as spoof surface plasmon polaritons and designer surface plasmons, are surface electromagnetic waves in microwave and terahertz regimes that propagate along planar interfaces with sign-changing permittivities. Spoof surface plasmons are a type of surface plasmon polariton, which ordinarily propagate along metal and dielectric interfaces in infrared and visible frequencies. Since surface plasmon polaritons cannot exist naturally in microwave and terahertz frequencies due to dispersion properties of metals, spoof surface plasmons necessitate the use of artificially-engineered metamaterials.
Arti Agrawal is a scientist and engineer known for her work on computational photonics as well as diversity, equity, and inclusion in STEM; she has been recognized in both of these areas by a number of awards. Her research is focused on numerical modeling and simulation of photonic devices and optical components. Agrawal is currently serving as Associate Professor and the Director of Women in Engineering and Information Technology at the University of Technology Sydney and Associate Vice President of Diversity for the IEEE Photonics Society.
Natalia M. Litchinitser is an Electrical Engineer and Professor at Duke University. She works on optical metamaterials and their application in photonic devices. Litchinitser is a Fellow of the American Physical Society, The Optical Society and the Institute of Electrical and Electronics Engineers.
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