Dr. B.D. Gupta

Surface plasmon resonance (SPR) is one of the most promising optical techniques that find applications in sensing of various chemical and biochemical parameters. In SPR technique, a TM (transverse magnetic) or p-polarized light causes the excitation of electron density oscillations (known as surface plasmon wave, SPW) at the metal-dielectric interface. When the energy as well as the momentum of both, the incident light and SPW, match a resonance occurs which results in a sharp dip in the reflected light intensity. The resonance condition depends on the angle of incidence, wavelength of the light beam and the dielectric functions of both the metal as well as the dielectric. To excite surface plasmons, generally, a prism is used. The prism based SPR sensing device has number of shortcomings which can be overcome if an optical fiber is used in place of prism. In recent years, surface plasmon resonance based optical fiber sensors have drawn lot of attention. Both experimental and theoretical investigations have been reported in the literature. The performance of these sensors is, generally, evaluated in terms of sensitivity and signal to noise ratio (or, detection accuracy). In the present talk we shall discuss the principle of the sensing technique including the description of the performance parameters of the sensor: sensitivity and signal to noise ratio or detection accuracy. Various designs of the fiber optic SPR probes that have been studied to enhance the performance of the fiber optic sensor will be discussed. The advantages of bimetallic coatings, addition of dopants in fiber core and the choice of the metals and semiconductors for coating will also be presented. In addition, we shall also discuss fiber optic SPR sensors for the detection of naringin, pesticide, ethanol in water, urea etc

BIOGRAPHY: B.D. Gupta received his M.Sc. degree in physics (1975) from Aligarh Muslim University (India) and a Ph.D. degree in physics (1979) from the Indian Institute of Technology, New Delhi. In 1978 he joined the Indian Institute of Technology, New Delhi, where he is currently a professor of physics. In addition, Prof. Gupta has worked at the University of Guelph (Canada) in 1982-1983, the University of Toronto (Canada) in 1985, the Florida State University (USA) in 1988, the University of Strathclyde (UK) in 1993 and the University of Birmingham (UK) in 2010. In 1992, he was awarded the ICTP Associateship by the International Centre for Theoretical Physics, Trieste (Italy), which he held for 8 consecutive years. In this capacity, he visited ICTP (Italy) in 1994 and 1996. Prof. Gupta is a recipient of the 1991 Gowri Memorial Award of the Institution of Electronics and Telecommunication Engineers (India). He has published more than 80 research papers including 5 review articles in international journals of repute. Prof. Gupta is authored a book entitled Fiber Optic Sensors: Principles and Applications (NIPA New Delhi, 2006) and is the Co-Editor of the Proceedings of SPIE (USA) Vol.3666 (1998) and Advances in Contemporary Physics and Energy (Supplement Volume) (Allied Publishers, New Delhi). His current areas of interest are plasmonics and fiber optic sensors. He is a regular member of the Optical Society of America and life member of the Optical Society of India and the Indian Chapter of ICTP.

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