10/08/2021 (Tuesday) 12:00 am |
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Workshop on Applied Optics and Optical Metrology for Steel Industry
Workshop on Applied Optics and Optical Metrology for Steel Industry
Abstract
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Workshop on Applied Optics and Optical Metrology for Steel Industry
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22/11/2017 (Wednesday) 02:00 pm |
S. Dutta Gupta
School of Physics, University of Hyderabad
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Photon anticoalescence with coupled modes
Photon anticoalescence with coupled modes
Abstract
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C 301,D2 |
08/11/2017 (Wednesday) 09:30 am |
Dinesh N.Naik
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Spectrally resolved incoherent holography
Spectrally resolved incoherent holography
Abstract
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C 301,D2 |
19/09/2017 (Tuesday) 09:30 am |
Jagroop Bhanwala
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ISRO Laser Gyro: An Overview
ISRO Laser Gyro: An Overview
Abstract
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C 201,D2 |
16/05/2017 (Tuesday) 02:00 pm |
Urbasi Sinha
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Fascinating world of photons,superposition and entanglement
Fascinating world of photons,superposition and entanglement
Abstract
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C 201,D2 |
17/02/2017 (Friday) 09:30 am |
Mark Mccaughrean
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ESA's Space Science and Exploration Missions
ESA's Space Science and Exploration Missions
Abstract
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Seminar Hall,D4 |
10/02/2017 (Friday) 09:30 am |
E. Krishnakumar
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Dissociation electron attachment in molecules
Dissociation electron attachment in molecules
Abstract
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C 301,D2 |
10/01/2017 (Tuesday) 02:00 pm |
Alok Kumar Singh
Stuttgart University,Germany
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3D Imaging with scattering media
3D Imaging with scattering media
Abstract
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14/10/2016 (Friday) 09:30 am |
Steen Gruner Hanson
Denmark Technical University
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How to Analyze,Utilize and Commercialize
How to Analyze,Utilize and Commercialize
Abstract
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IIST |
17/08/2016 (Wednesday) 02:00 pm |
N Apurv Chaitanya
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Non-linear interactions of structured optical beam
Non-linear interactions of structured optical beam
Abstract
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IIST |
02/05/2016 (Monday) 09:30 am |
Kedar Khane
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Sparsity assisted Optical Phase Imaging
Sparsity assisted Optical Phase Imaging
Abstract
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IIST |
09/03/2016 (Wednesday) 10:00 am |
Dinesh N.Naik
School of Physics, University of Hyderabad
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Optical Vortex beam from superposition of two gaussian beam
Optical Vortex beam from superposition of two gaussian beam
Abstract
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IIST |
27/01/2016 (Wednesday) 03:00 pm |
Nandan Singh Bisht, Dept of Physics, Kumaun University
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Generation and Characterization of Broadband Polarization Entangled Photons
Generation and Characterization of Broadband Polarization Entangled Photons
Abstract
In the recent past, the spectral control of biphotons generated from spontaneous parametric down-conversion (SPDC) has attracted great interest. In particular, there have been a number of experimental reports on the generation of broad-band biphotons with frequency anti-correlations because of their potential applications in the new field of quantum optical technologies, which includes such areas as entangled photon distribution using a wavelength-division multiplexing technology.
Here I will be discussing a pulsed broadband type-II biphoton source by exploiting the weak birefringence property of a periodically poled MgO-doped stoichiometric LiTaO3 (PPMgSLT) crystal and its spectroscopic and interferometric characteristics. For the characterization scheme, the conventional spectroscopic and two-photon interference techniques will be discussing. Further, the recent developments in entangled photon based quantum techniques will cover in this talk.
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C 201, D2 |
18/05/2015 (Monday) 11:00 am |
S. Dutta Gupta
School of Physics, University of Hyderabad
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Nonlinear optical PT-symmetric systems: Cavity control and regularization of spectral singularity
Nonlinear optical PT-symmetric systems: Cavity control and regularization of spectral singularity
Abstract
In recent years there has been a great deal of interest in parity-time (PT)-symmetric systems. Initially most of the attention was given to the fundamental conceptual aspects. Of late people are thinking of putting these fundamental ideas in action in the form of devices. Optics plays a major role in this direction. In my lecture I review some of the recent trends in PT-symmetric optical systems. Very many directions are emerging, which probe the feasibility and potential applications of the underlying physics. There have been attempts to combine the notions of recently invented coherent perfect absorption (CPA) and PT-symmetry to arrive at PT-CPA lasers [1]. One of the most important features of uasi-one dimensional PT-symmetric system is the spectral singularity [2]. At the singularity there is a divergence of scattered amplitudes, since the poles of the scattering coefficients occur on the real frequency axis,leading to zero width resonances. Since diverging scattere d fields are some mathematical abstractions and cannot exist in reality, there were recent attempts to bring in nonlinear ity to regularize the singularities. Note further that very little has been done on nonlinear aspects with most of the studies fo cusing on Kerr nonlinearity. Liu et. al. convincingly demonstrated that regularization can be achieved only by a s aturation type nonlinearity as in the power broadened response of a two level system [3]. We review some of these res ults and report on the PT -phenomena in cavity configuration. We pick two coupled cavities enclosed in a rin g cavity to show that cavities can drastically alter the specifics of the PT -resonance [4], to the extent of shift and regularization of infinities. This control along with the bi- and multi-stable output can lead to interesting devi ce applications [5]. To be specific we demonstrate optical isolation which can never be obtained in linear systems. The discussion is accompanied by a proof of nonreciprocity of transmission in nonlinear one dimensional systems. References- S. Longhi, “ PT symmetric laser absorber,” Phys. Rev. A 82 , 031,801 (2010).
- A. Mostafazadeh,“Spectral singularities of complexsca ttering potentialsand infinite reflection andtransmission coefficients at real energies,” Phys. Rev. Lett. 102 , 220,402 (2009).
- X. Liu, S. D. Gupta, and G. S. Agarwal, “Regularization of t he spectral singularity in PT -symmetric systems by all-order nonlinearities: Nonreciprocity and optical i solation,” Phys. Rev. A 89 , 013,824 (2014).
- G. S. Agarwal and S. D. Gupta, “Coupled optical bistable sy stems,” Phys. Rev. A 30 , 2764–2766 (1984).
- K. N. Reddy and S. Dutta Gupta, “cavity-controlled spectr al singularity,” Opt. Lett. 39 (2014).
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C-201, D2 |
28/01/2015 (Wednesday) 03:30 pm |
Apoorva Nagar IIST, Thiruvananthapuram
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Modeling ant traffic
Modeling ant traffic
Abstract
Observations on collective motion of ants have revealed features that are very different from car traffic. In our work, we have tried to explain these features using the Langevin equation with forces that include feedback mechanisms inspired from ant behavior.
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C303, D2 |
28/01/2015 (Wednesday) 02:30 pm |
Saptarshi Mandal ICTP, Trieste, Italy
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Few topological aspects in an exactly solvable spin model
Few topological aspects in an exactly solvable spin model
Abstract
In this talk we discuss some topological aspects in an exactly solvable spin model, namely the Kitaev model. We consider various manifestations of topological order, such as in the spin-spin correlation function, spin fractionalization and topological degeneracy of eigenstates. We also present results from an entanglement study, highlighting how it is related to the topological properties. Finally, we briefly discuss a three dimensional extension of the model, its exact solution, and the nontrivial statistics of the excitations.
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C303, D2 |
19/01/2015 (Monday) 03:00 pm |
M. Lakshmanan Bharathidasan University, Tiruchirappalli
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Understanding Nonlinearity and Unraveling Nature
Understanding Nonlinearity and Unraveling Nature
Abstract
I will present an overview of the relevance of nonlinearity in describing the evolution of dynamical systems (ranging from astrophysical systems to nanosystems) and consequent understanding of the underlying physical phenomena. I will also briefly discuss some of the potential technological applications.
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Seminar Hall, D4 |
08/11/2014 (Saturday) 02:00 pm |
G. Rangarajan IISc, Bangalore
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Are You Connected? Detecting Connectivity Patterns in Networks
Are You Connected? Detecting Connectivity Patterns in Networks
Abstract
Detecting connectivity patterns in a network of nodes/processes is crucial to the subsequent analysis of the network structure. Once these connectivity patterns are detected, there is also tremendous interest in determining how these patterns change with time. This is important since changes in connectivity patterns can serve as functional biomarkers for the onset of diseases or can be used to detect changes in the underlying states. Granger causality (first proposed by the Nobel Prize winning economist Clive Granger) is a tool that can be used to detect and quantify connectivity patterns. We propose extensions of Granger causality that enable it to be applied to a much wider variety of complex systems. We also demonstrate how changes in connectivity patterns can be measured using these extensions.
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Seminar Hall, D4 |
20/08/2014 (Wednesday) 02:30 pm |
YongKeun Park KAIST, South Korea
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Scattering superlens: subwavelength light focusing and imaging via wavefront shaping in complex media
Scattering superlens: subwavelength light focusing and imaging via wavefront shaping in complex media
Abstract
We present a novel method exploiting multiple scattering to achieve subdiffraction limited focusing and imaging using visible light. The sub-wavelength information at evanescent near-field are controlled by or transferred into propagating far-field components by elastic scattering from disordered nanoparticles.
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Seminar Hall, D4 |
22/07/2014 (Tuesday) 02:30 pm |
Suresh C Pillai Institute of Technology Sligo, Ireland
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Band Gap Engineering for making TiO2 Visible Light Active
Band Gap Engineering for making TiO2 Visible Light Active
Abstract
Semiconductor based photocatalytic technology has become an attractive candidate as a green process for environmental applications. Photocatalysis is used as a clean and green methodology to degrade microbes, toxic organic chemicals, industrial dyes, pesticides from the farms, volatile organic compounds and harmful gases from commodity goods. Semiconductor nanomaterials offer the potential for eliminating micro-organisms from various surfaces. TiO2 photocatalysts (band gap of 3.2 eV) on which most of the research has focused until recently, showed a relatively high photo-reactivity and self-sterilisation under ultraviolet (UV) light (wavelength <387 nm). The development of photocatalysts that can yield high self sterilisation under visible light (>400 nm) is desired in order to make use of the main part of the solar spectrum and to extend their applications to room interiors where there is relatively poor lighting illumination. Chemical modifications of TiO2 lattice using non-metals such as C,N,Sappeared promising strategies to reduce the band gap and thereby to improve visible light responsive photocatalytic activity.
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Audio-Visual Lab, D2 |
17/03/2014 (Monday) 03:00 pm |
Shyjumon Ibrahimkutty Karlsruhe Institute of Technology, Germany
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Synchrotron Small Angle X-ray Scattering (SAXS) analysis on Nanosystems
Synchrotron Small Angle X-ray Scattering (SAXS) analysis on Nanosystems
Abstract
SAXS is a fundamental method for structural analysis of condensed matter with applications covering various fields, from metal alloys to synthetic polymers in solution and in bulk, biological macromolecules, nanoparticles, etc. As the SAXS measurements are done very close to the primary beam ("small-angles"), the technique profits immensely from the brilliance of X-ray photon beams provided by particle accelerators known as synchrotrons. In this talk a detailed overview on the principles and application of synchrotron SAXS for the analysis of Nanosystems will be explained with the help of two relevant examples; “Gas phase analysis of silica mesostructure” and “Nanoparticles formation by laser ablation”.
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C201, D2 |
12/02/2014 (Wednesday) 03:00 pm |
Kota Murali IBM-India, Bangalore
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Nanotechnology - Enabling the future
Nanotechnology - Enabling the future
Abstract
The revolution in information and micro/nano electronics technology has been possible due to the continuously shrinking transistor. The size of the transistor has shrunk by more than 5 orders of magnitude in 5 decades ! Can this scaling continue, and would the Moore's law continue to hold ? These are some of the important questions facing nanotechnology community. As the devices enter nanoscale dimensions, many novel quantum effects start to dominate and these effects become important to design next generation devices. In this talk we shall discuss some important quantum effects and devices related to CMOS devices, spintronics, MRFM, computational lithography, silicon nanophotonics, and beyond silicon devices.
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Seminar Hall, D4 |
10/01/2014 (Friday) 03:00 pm |
A. K. Kapoor BITS, Hyderabad
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Recent developments in quantum Hamilton Jacobi method
Recent developments in quantum Hamilton Jacobi method
Abstract
Quantum Hamilton Jacobi Method was proposed originally proposed as a scheme to compute energy eigenvalues without need to solve the Schrodinger equation for the wave function first. Since its original formulation, it has been applied to a variety of problems. Important results in the formalism and recent results a will be summarized. Some further possible directions of research are indicated.
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C201, D2 |
09/12/2013 (Monday) 03:00 pm |
R. Shankar BHU, Varanasi
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Spectroscopy of multiply charged molecular ions induced by keV-electrons and studied by ion-ion coincidence technique
Spectroscopy of multiply charged molecular ions induced by keV-electrons and studied by ion-ion coincidence technique
Abstract
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C201, D2 |
05/12/2013 (Thursday) 03:30 pm |
Deshdeep Sahdev IIT Kanpur
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Indigenous technology in a globalized world: A case study
Indigenous technology in a globalized world: A case study
Abstract
It is an interesting and remarkable fact that every Nobel-prize winning piece of work in Experimental Physics has been carried out on apparatus which has been designed and developed by the physicist in question, be it Raman, Mossbauer or Binnig. This makes the question of how we build an instrumentational base for cutting-edge research in India relevant. I will discuss this in the context of several hi-tech instruments which my team has developed: Scanning Tunneling Microscopes for various applications, a Physical Properties Measurement System, Mass Flow Controllers, and Data Acquisition Systems --- to mention but a few. The talk will, in addition, focus on how the expertise we have built up can help in facilitating research (in the pertinent fields) at all our institutions.
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Seminar Hall, D4 |
23/10/2013 (Wednesday) 03:00 pm |
Bindusar Sahoo IISER Thiruvananthapuram
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Nobel Prize in Physics 2013
Nobel Prize in Physics 2013
Abstract
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Seminar Hall, D4 |
07/08/2013 (Wednesday) 04:00 pm |
ECG Sudarshan University of Texas, Austin, USA
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Reminiscences
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Seminar Hall, D4 |
07/08/2013 (Wednesday) 03:00 pm |
Rudra Sekhar Manna Goethe University, Frankfurt, Germany
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Low-dimensional frustrated quantum magnets
Low-dimensional frustrated quantum magnets
Abstract
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C201, D2 |
30/07/2013 (Tuesday) 02:00 pm |
Joby Joseph Dept. of Physics, IIT Delhi
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Photonic Structure Devices through Interference lithography & Direct Laser Writing
Photonic Structure Devices through Interference lithography & Direct Laser Writing
Abstract
Optical interference and holography has long been a powerful tool in many areas of optics such as precision measurement, and information processing/storage etc. Recently researchers have found a great potential in two and multiple beam interference techniques in forming 2-D and 3-D volumetric structures in photosensitive materials. Even though, the fabrication of photonic structures on relevant length scales (i.e., nanometer, sub micrometer, and micrometer) can be achieved by means of various techniques such as electron or ion beam writing, deposition methods and self assembly, the prime advantage of interference lithography is, to fabricate large area defect-free nano-photonic structures both rapidly and cheaply. The presentation gives an overview of the technique of interference lithography in combination with direct laser writing for photonic structure fabrication, and describes novel reconfigurable phase engineering based fabrication technique which is least complex and provide more flexibility compared to existing techniques at the same time this technique is capable of fabrication highly complex photonic structures. Direct laser writing through precise motion control has the capability to write complex as well as well defined nano structures in various choice materials. Combining interference lithography and direct laser writing increases the capability of fabrication of photonic structures for many applications of futuristic photonic circuits and photonic devices.
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Seminar Hall, D4 |
27/06/2013 (Thursday) 03:00 pm |
Sreedhar B. Dutta IISER Trivandrum
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K.G. Wilson - A Tribute
K.G. Wilson - A Tribute
Abstract
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Seminar Hall, D4 |
09/04/2013 (Tuesday) 03:00 pm |
Christophe Chatelain Institut Jean Lamour, Universite de Lorraine, France
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The influence of disorder on the phase transition of the Potts model
The influence of disorder on the phase transition of the Potts model
Abstract
The Potts model is a lattice spin-model introduced as a simple generalisation of the Ising model. Classical degrees of freedom, called spins, take q possible states and interact by pairs between neighbouring sites of the lattice. In 2D, the model undergoes a second order phase transition for q<=4 and a first-order one for q>4. We will discuss the influence of disorder coupled to the energy. The first-order phase transition is smoothed by randomness and becomes continuous for any strength of the disorder. In 3D, a first-order regime survives at weak disorder and terminates at a tricritical point. We will then discuss the influence of a disorder preserving translation invariance along one space dimension, like in the McCoy-Wu model. Finally, we will present recent results on 2D Potts models with long-range correlated results.
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C106, D4 |
27/03/2013 (Wednesday) 03:00 pm |
R. Shankar Instutite of Mathematical Sciences, Chennai
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Accelerated Climate Change and the response of Himalayan Glaciers
Accelerated Climate Change and the response of Himalayan Glaciers
Abstract
We review the scientific evidence that the climate of the earth is currently changing at a rate that is much faster than in the past 8 lakh years or so and that this phenomenon is due to human activities. We will then discuss the response of the ice in the Himalaya to the rapid warming of the globe. We summarise the data available and discuss some of the problems involved in modelling the system to predict the fate of the Him in the Himalaya
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Seminar Hall, D4 |
20/03/2013 (Wednesday) 03:00 pm |
A.P. Balachandran Syracuse University, USA
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Magnetic Monopoles and Quantum Physics
Magnetic Monopoles and Quantum Physics
Abstract
Magnetic monopoles are the analogues of charges for magnetic fields and produce Coulomb-like magnetic fields. They were studied by Dirac in 1931 and have striking physical consequences. Their existence predicts quantisation of electric charge. Also, in 'grand unified' models, they catalyse proton decay at extraordinarily fast strong-interaction rates. The reason for these striking consequences is that wave functions are not really ordinary functions .The talk explains how this is so and how their subtle aspects already show up in the quantum mechanics of spinning particles.
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Seminar Hall, D4 |
06/03/2013 (Wednesday) 03:00 pm |
G. G. Sivjee Embry Riddle Aeronautical University, USA
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Technological Challenges arising from Space Disturbances
Technological Challenges arising from Space Disturbances
Abstract
Variations in the Solar Modulations of the Near Earth Space Environment impact satellite communications, ground-based power grids, oil and gas pipe lines, terrestrial weather as well as many other systems that play crucial roles in our modern day living. In this talk, we will review the basics of Solar-Terrestrial Interactions and current efforts to predict their disruptive effects on various technologies and environment
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Seminar Hall, D4 |
30/01/2013 (Wednesday) 02:00 pm |
N. Bhargava Ram RRI, Bangalore
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Probing molecular chirality with a femtosecond reaction microscope
Probing molecular chirality with a femtosecond reaction microscope
Abstract
In this talk, I will describe the phenomenon of 'photoelectron circular dichroism (PECD)' arising in chiral molecules and present details of the experiments performed on molecules such as camphor, borneol with femtosecond laser pulses and a velocity map imaging spectrometer for detecting electrons and ions in coincidence. This research work was pursued as a post doc at LaserLaB, VU university, Amsterdam during 2010-2012.
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C201, D2 |
09/01/2013 (Wednesday) 03:00 pm |
Mitsuo Takeda Utsunomia University, Japan
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Coherence Holography
Coherence Holography
Abstract
Coherence plays fundamental role in holography and optical interferometry that are now widely used as indispensable tools in scientific and industrial metrology. High coherence of laser light has enabled holographic interferometry and speckle metrology, while low coherence of white light has made possible absolute 3-D shape measurement and optical coherence tomography by means of low-coherence interferometry. This talk will shed light on time-space analogy in the role of coherence functions in optical metrology, and introduce the principle and the applications of a recently proposed unconventional holographic technique, called coherence holography. In coherence holography, the information of the 3-D object is encoded into the spatial coherence function of the reconstructed optical field. Instead of detecting the image as the optical field intensity, coherence holography detects the image as a degree of spatial coherence between a pair of points, of which one serves as a reference point and the other as a probe point. Just as a conventional computer-generated hologram can create a three-dimensional image of a non-existing object, a computer-generated coherence hologram can create an optical field with a desired three-dimensional spatial coherence function, enabling coherence synthesis or coherence shaping, which will open up new possibilities for dispersion-free spatial coherence tomography and 3-D profilometry.
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Seminar Hall, D4 |