Qualification: 
Ph.D, MSc, M.Tech
sreenivasannairsk@am.amrita.edu

Dr. S. K. Sreenivasan Nair currently serves as Professor, Department of Physics, Amrita School of Arts and Sciences, Amritapuri. Dr. Nair worked at the Bio-medical Engineering division of Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, during 1986-94 and as a Scientific Officer at Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai and Raja Ramanna Centre for Advanced Technology, Indore during 1994-2010. He had also served as a Professor at Toc H Institute of Science and Technology, Ernakulam, during 2010-2016.

Dr. Nair is interested in design, development and testing of Solid State Lasers for various applications and has independently developed laser marker systems, several research lasers including arc lamp pumped and diode pumped Nd: YAG lasers, dye lasers, laser beam analyzer, optical testing devices etc. He was also a Visiting Faculty in International School of Photonics, CUSAT, Kochi, since 2011 till May 2017.

Education

  • 2009: Ph.D. in Physics
    Bhabha Atomic Research Centre, Mumbai University 
  • 1991: M.Tech. Applied Optics
    Indian Institute of Technology, Delhi
  • 1987: M. Sc. Physics
    Annamalai University

Publications

Publication Type: Conference Paper

Year of Publication Publication Type Title

2014

Conference Paper

A. P. R. and S. K. Sreenivasan Nair, “Diode Pumped Solid State Lasers: An Overview”, in National Workshop on Recent Advances in Lasers for Communication, Signal and Material Processing, 2014, pp. 12-14.

2014

Conference Paper

A. P. R, P, D., and S. K. Sreenivasan Nair, “Study on the efficiency improvement of Diode Side Pumped Solid State Lasers”, in Innovations & Advances in Science, Engineering & Technology Organised by Toc H Institute of Science & Technology in association with BRNS, ISTE, IJIRSET, CSI, 2014.[Abstract]


Improving the efficiency of Diode Pumped Solid State Laser (DPSSLs) is a challenging job ever since the discovery of DPSSLs. End pumped DPSSL has an inherent advantage of higher coupling efficiency compared to side pumped DPSSLs due to higher absorption length for the input diode power. However this technique is not applicable to high power DPSSL especially above 100 W CW lasers as the laser crystal cannot withstand the very high pump power density and the get fractured under thermal stress. Therefore, obviously side pumping is the only option for high power DPSSLs typically above 100 W average power. The limitation of side pumping is the lower absorption length and multiple reflection of diode power is required for efficient use of pump power. This is partially solved by increasing the doping concentration but the lower beam quality is the price to be paid for it. Further doping concentration cannot be increased beyond certain level as the crystal breaks under strain developed by the dopant. This introduces stringent design constraints for high power DPSSL and also limitations to the power coupling. Furthermore bare diodes have typical divergence of 40 to 50 deg and very close coupling becomes essential for efficient utilization of diode power. Use of micro-lens array is the usual solution, but this reduces the available diode power to be coupled to the laser crystal due to Fresnel reflections leading to reduction in overall efficiency of the system. Thus the laser head design becomes a real challenge for any designer working with high average power DPSSLs. In this paper we describe various techniques employed to improve the overall efficiency of diode side pumped DPSSL.

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2014

Conference Paper

A. P. R., ,, Nair, M. D., P., D., and S. K. Sreenivasan Nair, “Wireless Measurement and Analysis of Low Frequency Vibration”, in Annual Photonics Workshop 2014, 2014.

2014

Conference Paper

A. P. R., Nair, M. D., Mohan, S., P., D., and S. K. Sreenivasan Nair, “Design of Portable Biometric Authenticator – Finger Vein PATTERN Recognition”, in Annual Photonics, Workshop 2014,, 2014.

2013

Conference Paper

C. .K.Deepthy, P.R., A., P., D., D, M., and S. K. Sreenivasan Nair, “Study on the Design and Development of Laser Beam Analyser”, in National Laser Symposium- (NLS - 21), BARC, Mumbai, 2013.

2012

Conference Paper

A. P. R, Deepthy, C. K., Nair, M. D., S. K. Sreenivasan Nair, and .P.N.Nampoori, V., “Measurement of low frequency vibrations and characterization of vibration isolation systems using interferometric methods”, in IAPT Seminar on “Recent Trends in Photonics” Organized by International School of Photonics, Cochin University of Science &Techology, , 2012.

2011

Conference Paper

S. K. Sreenivasan Nair, “Design and development of High Efficiency Laser Reflectors”, in National Seminar on Horizons in Thin Film Technology, Toc H Institute of Science & Technology, Ernakulam, 2011.

Publication Type: Journal Article

Year of Publication Publication Type Title

2012

Journal Article

S. K. Sreenivasan Nair, “Influence of temperature on the performance of Diode Pumped Solid State Lasers”, TIST International J of Science, Technology and research, vol. 1, pp. 13-18, 2012.

Publication Type: Conference Proceedings

Year of Publication Publication Type Title

2011

Conference Proceedings

S. K. Sreenivasan Nair, “Studies on the Design, Development and Optimization of High Average Power Diode Pumped Solid State Lasers”, Proceedings of National Symposium on Atomic, Molecular and Optical Physics. Karnatak University, Dharwad., 2011.

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