ASIAN JOURNAL OF PHYSICS

It gives me great pleasure to express my admiration and share Prof. D. Narayana Rao’s scientific contributions to the field of laser spectroscopy and nonlinear optics. I had a chance to know him in 1988 when he joined my group as a CSIR Pool Officer. He took very active interest in establishing a Holography lab and introduced several experiments for the M Sc students. At that time, I was looking for a scientist who could develop experimental laboratories in laser spectroscopy. Narayana had the right background, having being trained in some of the best laboratories in India and USA. Thus, we decided to hire him for the middle level faculty position and provided funding for starting research laboratory.
He came to me in search of a position in India after working for many years in Prof. Paras N. Prasad’s lab at State University of New York at Buffalo, NY, USA. He did his Ph D under the guidance of Prof. Ramachandra Rao Dasari, and the well-known scientist Professor, P. Venkateswarlu. His Ph D work was on “Site selective fluorescence spectroscopy from the rare-earth doped calcium fluoride crystals”. From his resume, I came to know that he joined the IIT Kanpur in the year 1971 after completing Master’s Degree from Sri Venkateswara University Post Graduate Centre at Anantapur in Andhra Pradesh. At IIT Kanpur he developed experimental skills on microwave spectroscopy of different organic gases, MW-Infrared double resonance to derive the absorption coefficients, distortion constants, harmonic generators to reach up to 54 GHz, Rare-earth doped crystal growth, development of CO2 laser, etc. After completion of his Ph D in 1978, he worked as a Research Associate under the joint guidance of Profs. K. P. Jain, S. C. Abbi and S. Chopra to develop the Raman Spectroscopy lab using an Ar+ laser in the Department of Physics, IIT Delhi. After working for a year there, he returned to IIT Kanpur as a scientific officer to assist Prof. Putcha Venkateswarlu. In 1981, he was offered a post-doctoral position in the Photonics Laboratory, State University of New York at Buffalo, USA under Prof Paras N. Prasad. He told me that quite a lot of development responsibility fell on him as he was from physics background and with good amount of instrumentation experience. His first publication was on the development of mixed gas FIR laser excited by CO2 laser, a region which is now popular with the name of THz. He went on working on ns Nd:YAG, ps ML and QS Nd:YAG laser, fs lasers staring from 300 fs to 60 fs dye laser at SUNYAB, USA. He started working on nonlinear optics problems such as: Transient grating spectroscopy, Coherent anti-Stokes Raman, CSRS, waveguide CARS, diffused reflectivity with FIR lasers, spectral diffusion in organic solids at supercooled liquid He temperatures.
After joining University of Hyderabad, he developed a strong collaboration with Dr. Dasari and Prof. M. Feld of MIT, Prof. D. Gopal Rao at UMASS, Boston, USA and University of Trento, Italy. It is quite amazing that he could produce nearly twenty-two Ph D scholars from this lab, which was an empty hall in 1991. He interacted with many scientists at University of Hyderabad and other institutions; to name a few Prof. Bhaskar Maiya, Prof. T. P. Radhakrishnan, Prof. Chandrasekher from Chemistry, Prof. Reddanna from Life Sciences. Nearly a dozen students from other departments and institutions have completed their Ph D work from his lab. Most of his students have settled as faculty members at different institutions in India and abroad.
He helped Prof. Tewari in establishing the ACRHEM in the initial stages. Three of his students are now professors in ACRHEM working on laser applications to high energy materials. He was quite dynamic in writing proposals to different funding agencies and received nearly 18 projects during a period of 25 years as a faculty in the School of Physics, University of Hyderabad. He also had three major projects with Trento University, Italy and one project with Australian National University as collaborative study in the area of nonlinear optics.
He worked on several area of spectroscopy and nonlinear optics: Microwave spectroscopy, Development of lasers, Fluorescence spectroscopy, crystal growth, Wolf shift, Spectral Interferometry, Incoherent Laser Spectroscopy, Studies on Local Fields, Ultrafast Dynamics, Transient Grating Spectroscopy, Coherent Anti- Stokes Raman Spectroscopy, Nonlinear Spectroscopy, Four Wave Mixing, Z-scan, 1D and 3D Photonic Crystals, Nanoplasmonics, Surface Enhanced Raman Spectroscopy, Supercontinuum Generation, Laser Ablation, Green Synthesis of Nanoparticles, and Laser Direct Writing.
In the initial stages I asked him to work on our theoretical predictions on spectral interferometry and Wolf shifts-he did do it successfully and produced a sensitive method of measuring refractive index. Given his expertise on rare earth halides, I asked him to prepare materials where refractive index could be controlled so that one test different models of local fields in dense media. He did such a study successfully which was published in Physical Review Letters.
He is close to three hundred refereed publications in international journals and presented an equal number in international conferences. He received NRC (USA) Fellowship, UGC-BSR Faculty Fellowship and DAE Raja Ramanna Fellowship. He is a Fellow of Academies of Telangana and Andhra Pradesh. As an Emeritus Professor, he is working on Antireflecting surfaces, Superhydrophobic surfaces, 1D and 2D Photonic crystal structures.
I have felt a great deal of satisfaction that I made the right choice in hiring him and entrusting him with the responsibility of developing modern laser spectroscopy. It must be added that in nineties, his lab became one of the few labs in India devoted to modern laser spectroscopy. I wish him all success in life.

G S Agarwal
Mitchell Physics Building IQSE 574, 4242 TAMU
College Station, TX 77843-4242
girish.agarwal@tamu.edu
April 19,2021, Monday.