An International Peer Reviewed Research Journal
Frequency : Monthly,
ISSN : 0971 – 3093
Editor-In-Chief (Hon.) :
Dr. V.K. Rastogi
e-mail:[email protected]
[email protected]

AJP ISSN : 0971 – 3093
Vol 30, No 7, July, 2021

Journal of Physics

Volume 30 No 7 July 2021

A Special Issue Dedicated
Prof Kehar Singh
Guest Edited By : Vinod Rastogi & H C Kandpal

About Prof Kehar Singh

Professor Kehar Singh served as a member of the faculty at IIT Delhi since 1965 in various capacities. He was an ‘Academic Visitor’ at Imperial College of Science & Technology, London during 1969-1970, and visited / carried out research for short periods at British Scientific and Industrial Research Association Ealing, Queen’s Univ. Belfast, and National Physical Laboratory Teddington. He had been a Professor since January 1984 and during the period 1996-1999 served as Head of Physics Deptt. Prof. Singh held the position of Dean, Post Graduate Studies and Research, IIT Delhi during the period of March 2001-Aug. 2003. He served as CLUSTER Chair at the Swiss Federal Institute of Technology, Lausanne (Switzerland) in Dec.2002. Until June 30,2011 he served as an Emeritus Professor at IIT Delhi where he continued to teach and carry out research.
Since 2011, he has been an Hony. Distinguished Research Professor at ITM (now NorthCap) University, Gurgaon (Haryana) where he mentors a group of faculty members and supervises research in the areas of Information Security, Singular Optics, and Nanophotonics (Photonic band gap structures, metamaterials, and plasmonics). Prof. Singh served for a number of years as Chairman of the Research Council, IRDE (Defense Research & Development Organization) Dehradun and a member of the Cluster Advisory Council for a group of DRDO laboratories. He also served as a Member of the Research Council of National Physical Laboratory New Delhi. Since May 2015, he has been working as an Associate Editor of Optics Express, a high impact factor journal of the Optical Society of America (OSA).
Prof Kehar Singh has been an active researcher and educator and created infrastructural facilities for teaching and research in his areas of specialization: Photonics/Information Optics (Image formation and evaluation, Dynamic holography, Nonlinear photorefractives, Optical correlators, Holographic storage, Digital holography, Singular optics, and Optical cryptography). He has published extensively, having authored / co-authored nearly 350 peer reviewed research papers. Besides these there are approx. 75 review articles in books and journals, and 70 papers in conference proceedings. His research papers have been cited extensively in the literature; one of the papers having been cited 1100 times..
Research publications by Prof. Singh and coworkers during the period 1965-1985 resulted in 11 Ph.D. theses. Since 1986, 20 students have completed Ph.D. degree under the supervision of Prof. Singh. Besides these, 75 Master of Technology and M.Sc. students have been guided in their dissertation work. He had been the backbone of the M.Tech. program in Applied Optics at IIT Delhi ever since it started in 1966. This program has produced many scientists who occupy key positions in India and abroad.
Professor Kehar Singh was honoured with Shanti Swarup Bhatnagar Award in Physical Sciences in 1985 by the CSIR, Govt. of India. He has been awarded in 2001, the Galileo Galilei Award of the International Commission on Optics. The Optical Society of India honoured him with the ‘OSI Award’. He was also given ‘Life Time Achievement Award’ at the OSI symp. held at Tezpur in Dec.2007,and Golden Jubilee ‘Distinguished Service Award’ of IIT Delhi in 2011.Prof Singh was also honored in 2011,under the Golden Jubilee ‘Honor the Mentor’ program’ of IIT Delhi.
Prof Singh is a Fellow of the Optical Society of America, SPIE (The International Society for Optical Engineering), and Indian National Academy of Engineering, in addition to being a Distinguished Fellow of the Optical Society of India and a Fellow of the Laser & Spectroscopy Society of India. He was President
of the Optical Society of India from 1991 to 1994 and its Vice-President from 1988 to 1991. He also served as the President of ‘Laser and Spectroscopy Society’ of India and was President, Indian Science Congress Association (Physical Sciences Section) in 2004. Prof. Singh had been an international advisory member of the editorial board of Optical Review (Japan, 1994-2010 ), Member of the editorial boards of Optics & Lasers in Engg. (Elsevier, 1999 – 2006). Currently he serves as an Associate Editor of Optics Express (2015—-todate), Computer Optics (Russia), J. Optics (India, 1974 – to date), Asian J. Phys. (1992 – to date). and Invertis J. Science and Technol (2007- ). He also served as an editorial board member of the Indian J. Pure Appl. Phys.(CSIR, 1986–88).
Prof Singh has been serving as a reviewer of research papers for several journals of repute. He has given approx. 100 invited lectures in various international and national conferences/seminars/workshops and has also been associated as member of organizing/technical/steering committees of several international and national conferences/seminars/ workshops. He has visited U.K, France, Italy, Switzerland, Germany, Czechoslovakia, Canada, USA, Mexico, Japan, South Korea, Australia, Singapore, and Indonesia for delivering lectures in conferences. He was one of the Directors of the II Winter College in Optics held at ICTP, Trieste, Italy during Feb-March, 1995.
Professor Singh’s research work attracted funding for sponsored research in the field of Optics and Photonics from a number of Govt. agencies such as Department of Science and Technology, Ministry of Human Resource Development, and Defense Research and Development Organization. He has served on many committees of the Govt. of India (e.g. Environmental Impact Assessment Committee, Ministry of Environment and Forests) and has been a consultant to some industries.
As Technical chair of the International Conference on ‘Optics and Optoelectronics’ held in Dehradun, India in Dec. 1998, Prof. Singh co-edited a two volume proceedings of the conference, and SPIE volume 3729, Selected papers from International Conference on Optics and Optoelectronics’98 (Silver Jubilee Symposium of the Optical Society of India). He was Technical co-chair of the International conference on Optics and Opto-electronics held in December 2005 at Dehradun, and Co-chair Advisory Committee of the OSI confer. held in Jan.2012 at IIT Delhi. He was Technical chair of OSI’s international conference held at GJ Univ.of Science &Technol. in Hisar, during the period Nov.23-26, 2017, and Chair International Advisory Committee of Photonics-2018 held at IIT Delhi during the period Dec.12-15,2018. Prof Singh was also the Technical Chair and Chair International Advisory Committee of the International Conference on Optics and Electro-optics held at IRDE Dehradun during the period Oct.19-22,2019. Proceedings of the conference have been published by Springer in 2021.
Professor Singh has edited / co-edited 2 special issues on ‘Photorefractives and their applications’ of J. Optics (India), 4 issues on ‘Optical pattern recognition’ and ‘Optical information security’ of Asian J. Physics, and a book on ‘Perspectives in Engineering Optics’ [2]
A book brought out by IIT Delhi, containing memoirs of some of the ‘Golden Jubilee Distinguished Award’ winner retired faculty members of IIT Delhi, has also been edited by Prof. Singh. A number of issues of Asian J. Phys. have been guest edited by him.
Prof Singh has also served as a member/chair of several national committees of the MHRD, CSIR, ISRO, DRDO, DST, and INAE. Besides having served as a consultant to some industries/organizations, he has also been a consultant on security holograms to some state Govts. in India. He served as a member of the Executive Committee, National Photonics Program DRDO, and is a member of the National Advisory Council, NorthCap University Gurgaon. He served as a member of the Board of Governors of Regional Engineering.College. Kurukshetra and served on the ‘Academic advisory councils’, ‘Board of Studies’ and ‘Research degree committees’ of several universities. He also served as an invited Senate member of National Institute of Technology Agartala (Tripura).

Asian Journal of Physics Vol. 30, No 7 (2021) 999-1005

Photorefractive smectic liquid crystalline mixtures and their application to remote sensing

Takeo Sasaki, Maho Hirakawa, Kaita Suzuki, Khoa Van Le, and Yumiko Naka
Department of Chemistry, Faculty of Science, Tokyo University of Science,
1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan

This article is dedicated to Prof Kehar Singh for his significant contributions to Optics and Photonics
on the occasion of his 80th Birth Day (July 3, 2021)

The photorefractive effect of flexoelectric smectic liquid crystal mixtures was investigated. Smectic liquid crystal mixtures, composed of smectic-C liquid crystals, photoconductive chiral compounds and a sensitizer, are known to exhibit a large photorefractive effect. The chiral compound plays a critical role in the exhibition of large photorefractivity in smectic liquid crystals. The concentration of the chiral compound was varied and the photorefractive properties of the liquid crystal mixture were examined. It was found that smectic-C liquid crystals containing small amounts of a chiral compound show a large photorefractivity even though they do not possess spontaneous polarizations. The application of the photorefractive liquid crystals to a remote sensing device was demonstrated. © Anita Publications. All rights reserved.
Keywords: Photorefractive effect, Liquid crystals, Asymmetric energy exchange, Remote sensing.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
Buy this Article in Print © Anita Publications. All rights reserved

  1. Sasaki T, Ikegami M, Abe T, Miyazaki D, Kajikawa S, Naka Y, Real-time dynamic hologram in photorefractive ferroelectric liquid crystal with two-beam coupling gain coefficient of over 800 cm–1 and response time of 8 ms. Appl Phys Lett, 102(2013)063306; doi. 10.1063/1.4792735.
  2. Solymar L, Webb J D, Grunnet-Jepsen A, The Physics and Applications of Photorefractive Materials, (Oxford: New York), 1996.
  3. Reshetnak V Yu, Pinkevych I P, McConney M E, Evans D R, Director grating and two-beam energy exchange in a hybrid photorefractive cholesteric cell with a helicoidal polymer network, J Appl Phys, 127(2020)125502; doi. 10.1063/1.5142079.
  4. Kippelen B, Peyghambarian N, Advances in Polymer Science, Polymers for Photonics Applications II, (Springer) 2002, p 87–156.
  5. Ostroverkhova O, Moerner W E, Organic Photorefractives: mechanisms, materials, and applications, Chem Rev, 104(2004)3267–3314.
  6. Sasaki T, Naka Y., Photorefractive effect in ferroelectric liquid crystals, Opt Rev, 21(2014)99–109.
  7. Sasaki T, Yoshino M, Naka Y, Le K V, Sassa T, Laser irradiation durability of photorefractive ferroelectric liquid crystal blends containing terthiophene photoconductive chiral dopants, RSC Adv, 6(2016)70573–70580.
Asian Journal of Physics Vol. 30, No 7 (2021) 1171-1178

The fronto-parietal attention network and the infantile nystagmus syndrome

Marija Strojnik
Centro de Investigaciones en Optica, Apdo. Postal 1-948, 37150 Leon, Gto., Mexico

This article is dedicated to Prof Kehar Singh for his significant contributions to Optics and Photonics
on the occasion of his 80th Birth Day (July 3, 2021)

We present an optical – information processing model of the human visual system, from casually moving the gaze onto an object to using the central executive network for consequent viewing decisions. We discuss how reflexive and conscious gaze-control decisions are made in the frontal eye field and the inferior parietal lobe, and initiate saccades. Cultural and spatial experiential learnings provide input to formulate our conscious decisions. We consider the consequences of the defective fronto-parietal attention network, presented by an individual with the infantile nystagmus syndrome on his viewing strategy and the potential limitations in his acquisition of visual information. We propose that such individual has near-nose convergence of eyes, and uses his eye muscles to reestablish gaze intermittently, with the eyes trying to return to their zone of comfort during each oscillation. This effort precludes healthy saccade employment. We conclude that an improper development of search mechanisms may result in a large amount of neglected information. © Anita Publications. All rights reserved.
Keywords: Vision, Modeling the vision, Retina; Ventral temporal pathway for object recognition (what ?), Dorsal parietal pathway for navigation (where?), Fronto-parietal attention network, Saccades, The central executive network, Nystagmus, Infantile nystagmus syndrome, Focusing optical systems, Image stabilisation.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
Buy this Article in Print © Anita Publications. All rights reserved

  1. Strojnik M, Scholl M K, Understanding human visual system and its impact on designs of intelligent instruments, in Honoring John Caulfield, Proc SPIE 8833, paper 3 (2013), and references therein;
  2. Kolb H, Fernandez E, Jones B W, Nelson R (eds).The Organization of the Retina and Visual System,
  3. Kandel E R, Schwartz J H, Jessell M T, Siegelbaum S A, Hudspeth A J, Principles of neural science, 5th edn, (McGraw-Hill, New York, NY), 2013, pp 557-576.
  4. Ptak R, The frontoparietal attention network of the human brain: action, saliency, and a priority map of the environment, The Neuroscientist, 18(2012)502–515.