Prasad Arvind Chaphekar

09 March 2026

• Email

Education / Work History

• Deputy Director (Income Tax) (present)
• M.Tech, Center for Lasers and Photonics (CELP), IIT Kanpur (2006-2008)

Thesis Abstract

Construction and Characterization of a Computer Controlled Acousto-optic Modulator based Femtosecond Pulse Shaper

Fourier pulse shaping of femtosecond pulses has lately gained a lot of im-portance , because of its varied applications in areas such as optical WDMAand CDMA communication systems, non-linear optics, biomedical applica-tions, spectroscopy, coherent control and so on. In this thesis , I reportthe construction and characterization of a "`Computer controlled femtosec-ond folded geometry pulse shaper using an Acousto-optic modulator". Wedemonstrate independent amplitude and phase modulation of femtoseondlaser pulses through computer control. The construction of a folded geom-etry AOM pulse shaper, the necessary modi cations to theory for foldedgeometry, and the experiments with amplitude and phase modulation areexplained in detail. The implementation of a genetic algorithm is discussed,which, when implemented on the setup, can arbitrarily shape a pulse to op-timize a certain quantity, for example, two-photon uorescence in a sample.I also propose a feedback loop implementation to achieve any desired pulseshape. I improved the acquisition and analysis speed of the pulse charac-terization technique "STRUT" by almost 8-10 times, which has made theimplementation of the feedback loop practically feasible.

Research Topic / Interest

Contact me to know my current interests.

Publications

These include only those published in our lab.

1. Applying Genetic Algorithm Optimization to a Folded Geometry Acousto-Optic Modulated Spatial Pulse Shaper. A. Nag, P. A. Chaphekar, and D. Goswami, Review of Scientific Instruments 81(1), 013101 (2010) [BibTeX]

    BibTeX: @article{nagApplyingGeneticAlgorithm2010,
     title = {Applying Genetic Algorithm Optimization to a Folded Geometry Acousto-Optic Modulated Spatial Pulse Shaper},
     author = {Nag, Amit and Chaphekar, Prasad A. and Goswami, Debabrata},
     year = {2010},
     month = jan,
     journal = {Review of Scientific Instruments},
     volume = {81},
     number = {1},
     pages = {013101},
     issn = {0034-6748},
     doi = {10/ddkc77},
     urldate = {2019-08-14},
     annotation = {GSCC: 0000008 \\
     5 citations (Crossref) [2024-05-28]\\
     00004}
   }
   

2. Applying Genetic Algorithm Optimization to a Folded Geometry Acousto-Optic Modulated Spatial Pulse Shaper. A. Nag, P. A. Chaphekar, and D. Goswami, Review of Scientific Instruments 81(1), 013101 (2010) [BibTeX]

    BibTeX: @article{nagApplyingGeneticAlgorithm2011,
     title = {Applying Genetic Algorithm Optimization to a Folded Geometry Acousto-Optic Modulated Spatial Pulse Shaper},
     author = {Nag, Amit and Chaphekar, Prasad A. and Goswami, Debabrata},
     year = {2010},
     month = jan,
     journal = {Review of Scientific Instruments},
     volume = {81},
     number = {1},
     pages = {013101},
     issn = {0034-6748},
     doi = {10/ddkc77},
     urldate = {2019-08-14},
     annotation = {GSCC: 0000008 \\
     5 citations (Crossref) [2024-05-28]\\
     00004}
   }