Dr. 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 University 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 Department. Prof. Singh held the position of Dean, Post Graduate Studies and Research, IIT Delhi, during the period of March 2001–August 2003. He served as CLUSTER Chair at the Swiss Federal Institute of Technology, Lausanne (Switzerland), in December 2002. Until June 30, 2011, he served as an Emeritus Professor at IIT Delhi where he continued to teach and carry out research.  Dr. A. K. Gupta is a DRDO Fellow and former Director & Outstanding Scientist, Instrument Research & Development Establishment (IRDE), a Defence Research & Development Organization (DRDO) laboratory at Dehradun. Dr. Gupta obtained his Ph.D. from IIT Delhi in the area of Optical/Photonics engineering, which has emerged as a potential enabling technology in 21st century for both civil & defence applications. Dr. Gupta has been actively involved in the development of electro-optical instruments for day & night surveillance and laser technologies for application to defence forces. He has made significant contribution in the development of technologies for laser seekers, laser proximity sensors, adaptive optics, integrated optics holography and optical information processing. Dr. Sudhir Khare is presently working as a Scientist at the Instruments Research and Development Establishment, Dehradun, India. He has been engaged in research, design and development in the area of thermal imaging for the last 25 years. His research interests include system design, IR signal processing and performance evaluation of thermal imaging systems. He is a member of the Optical Society of India.  Dr. Nimish Dixit obtained his Ph.D. from the Indian Institute of Technology, Bombay, India. After completing his Ph.D., he joined the Instrument R & D Establishment (IRDE), Dehradun. Since joining IRDE Dehradun, he has been engaged in the development of nonlinear frequency conversion laser systems in which he developed mid-IR tunable optical parametric oscillator (OPO). Of late, he has been responsible for starting the development of THz sources based on nonlinear optical methods. He is a Fellow of the Optical Society of India and a member of the Indian Laser Association. His current research includes generation of THz using nonlinear frequency conversion and THz imaging.     Kamal K Pantis  received his MTech degree in applied optics from IIT Delhi, India. Currently, he is working as a scientist in Instruments Research and Development Establishment, Dehradun. His research interests are development of freeform optics and diffractive optics for imaging applications, subaperture stitching-based metrology of freeform optics, and Shack–Hartmann sensor-based metrology.