An International Peer Reviewed Research Journal

Title Vol 28 Nos 7-9(2019)

AJP

SSN : 0971 - 3093

Vol 28, Nos 7-9, July-September, 2019


Asian


Journal of Physics

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Volume 28, Nos 7-9, July-September 2019

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A special issue on

Optics and Photonics

dedicated to


Eminent Scientist and Scholar Prof Ajoy Ghatak

M N Saha Distinguished Professor of NASI (The National Academy of Sciences, India)

and Formerly Professor of Physics at IIT Delhi
on his 80th birthday Nov 9, 2019



Anita Publications
FF-43, 1st Floor, Mangal Bazar, Laxmi Nagar, Delhi-110 092, India

Prof Ajoy Ghatak

                Professor Ajoy Ghatak is an eminent Indian scientist and a teacher per excellence on Optics and Photonics and celebrated former Professor of Physics at IIT Delhi, who is known all over the world for his significant research work on photonics, fiber optics and education in India and for his lucidly written outstanding books on Optics, Lasers, Quantum Mechanics and Relativity. Professor Ghatak has created a legacy of pride for the country and is commended as “one of the most eminent scientists in Optics and Photonics in general of all times in India”. Professor Ghatak was born on November 9, 1939 at Lucknow. He received his B Sc from Agra College, M Sc from Delhi University and Ph D from Cornell University, USA.

Prof Ajoy Ghatak

                After a short stint as a Research Associate at the Brookhaven National Laboratory,  USA, Professor Ghatak joined the Indian Institute of Technology Delhi, in 1966, where he was a Professor of Physics from 1974 till his retirement. Professor Ghatak has more  than 170 research papers  to his credit  in various International  journals and more  than 20 books.

                His book on Optics (translated into Chinese and Russian also) is very extensively used all over as a text in undergraduate teaching and in addition one on Fiber Optics, and another on Optical Electronics, and one on Quantum Mechanics are also very widely used for senior UG and PG courses as texts in these subjects.  His research contributions have been recognized through his induction as a Fellow of OSA.The Optical society, SPIE, NASI, OSI, and numerous international and national prestigious awards like SSB award of CSIR, Galileo Galilei award of ICO, Beller medal of OSA, SPIE Educator award and MN Saha award of UGC. As a current M N Saha Chair Professor of NASI he continues to contribute tirelessly and significantly to the progress and dissemination of knowledge in Optics, Photonics, and Quantum Physics. Even at his late-70 age, he can be seen frequently travelling to various colleges, institutions far-and-wide across the country to deliver tutorial level talks and also to disseminate knowledge on contributions made by Indian Scientists to motivate generation X students to take up teaching and research as a profession. He has published several popular science level books on Albert Einstein based on his personal research on Einstein’s monumental and iconic research.  One of Prof Ghatak’s seminal contributions in Guided Wave Optics has been his analysis and work on the physics of leaky modes in optical waveguides in a single-authored paper that had appeared in the Springer journal: Optics and Quantum Electronics in its September 1985 issue. This work eventually led to development of a Matrix method (IEEE J. Lightwave Tech. May 1987) for treating optical waveguides (and also optical fibers), which became an extremely powerful research tool for designing a variety of guided wave components and specialty optical fibers. This method found extensive use by other  researchers including Prof Ghatak himself  in numerous  international  journal publications on optical waveguide  and fiber designs for  realization of  components  thereof including quantum well devices.

About the Guest Editor
    Bishnu Pal born on Dec 3, 1948 in Shillong India is currently Professor of Physics and Dean of Academics at Mahindra École Centrale Hyderabad, India. He has been Former Chair of Physics Department (2007-2011) and Computer Services Centre at IIT Delhi (2003-2006) India, Member Board of Directors of OSA The Optical Society (Washington, USA, 2009-2011), Fellow of OSA the Optical Society (USA) and SPIE The International Society for Optics and Photonics (USA), Distinguished Honorary Member of Royal Norwegian Academy of Sciences and Letters (DKNVS, Norway), Senior Member of IEEE (USA) and Distinguished Lecturer of IEEE Photonics Society (2005-2006), Fellow and President of Optical Society of India (2012-2015), Alexander von Humboldt Fellow (1982-83, Germany) and Fulbright Scholar at NIST Boulder CO (1991, USA), PDF and latter Visiting Professor of Royal Norwegian

Bishnu Pal

CSIR (NTNF, Oslo, 1975-77) at Norwegian University of Science and Technology Trondheim Norway, awardee of Esther Hoffman Beller Medal of OSA, The Optical Society (Centenary Year 2016, USA), Invited faculty at the ICO Winter School in Optics held at ICTP 1998, Awardee of Homi  Bhabha award in Applied Physics of UGC (India, 2006), Om Prakash Bhasin award in Electronics and Information Technology (India, 2013), Khosla Research Award of IIT Roorkee (India, 2014) for lifetime contributions in research, Prof Y T Thathachari award for excellence in Physical Sciences (India, 2010) of Brhamara Trust (Mysore), CEOT award of IETE (India, 2010) for his contributions to Optoelectronics Devices, Co-recipient of the Fiber Optics Person of the Year award (1997) established by Lucent Technology in India and Optics award of Optical Society of India (OSI, 2010) for lifetime achievements.


Asian Journal of Physics                                                                                                           Vol. 28 Nos 7-9, 2019, 00-00


Towards stable delivery of high energy through background-guided similariton pulses


Piyali Biswas and Somnath Ghosh

Department of Physics,
Indian Institute of Technology Jodhpur-342 037
, Rajasthan, India

This paper is dedicated to Prof A Ghatak on his 80th birthday

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Stable delivery of high energy optical pulses through fibers is an attractive field of research owing to its wide applications in defense, bio-medical industry, chemical industry and so on. Delivery of such high energy can be possible by exploring the inherent potential of background-guided parabolic optical pulses. Asymptotic evolution of parabolic pulses largely depends on the initial pulse energy fed at the input of the fiber. Here, we have investigated the effect of presence of a hyperbolic tangent pulse as the background of an input Gaussian pulse. Further, we have numerically demonstrated the stable propagation of the evolved parabolic pulse with its characteristic linear chirp. A background-guided Gaussian pulse and a background-guided hyperbolic secant pulse, centered at 980 nm wavelength, have been fed at the input end of a dispersion decreasing Bragg fiber and allowed to propagate over several kilometers of the fiber length. The entire propagation has come out to be more stable, and shows closer asymptotic behavior in comparison with the conventional propagation of a single Gaussian or a single hyperbolic secant pulse of same energy. Such a scheme should be attractive in stable delivery of high energy pulses including applications in mid-IR spectroscopy, defense and medical surgery. © Anita Publications. All rights reserved.

Keywords: Parabolic pulse, Nonlinear fiber optics, High energy pulse, Similaritons.

Towards stable delivery of high energy through background-guided similariton pulses.pdf
Piyali Biswas and Somnath Ghosh

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Asian Journal of Physics                                                                                                           Vol. 28 Nos 7-9, 2019, 00-00


Optical Tweezers - the invention of which got the 2018 Nobel Prize in Physics


Pradeep Kumar Gupta

Physics Department, IIT Delhi, Hauz Khas, New Delhi-110016


Invited paper dedicated to Professor Ajoy Ghatak on his 80th Birthday

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The widespread applications of optical tweezers particularly in biological sciences have led to the award of one half of the Nobel Prize in Physics for the year 2018 to its inventor Arthur Ashkin. In this article, I briefly describe some aspects of the work carried out by us on the use of optical tweezers for transport, rotation/orientation and sorting of microscopic objects.  Use of the optical tweezers for the measurement of visco-elastic parameters of biological objects is discussed next. The use of optical tweezers to acquire spatially resolved Raman spectra from optically trapped cells and some results obtained using these so-called Raman Tweezers are also presented. © Anita Publications. All rights reserved.

Keywords: Optical Tweezers, Laser manipulation of microscopic objects, Raman tweezers

Total Refs :  27

Optical Tweezers - the invention of which got the 2018 Nobel Prize in Physics.pdf
Pradeep Kumar Gupta

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