Indian Institute of Technology, Patna

Dr. Raghavan K Easwaran

Dr. Raghavan K Easwaran

Associate.Professor

Ph.D, University of Paris 13, France , MSc in Physics IIT Madras

Ph: +91-612-3028029 Mob:- +91 7542957634

raghavanke[*AT]iitp.ac.in

Office Location: Science Block, 04/121, Indian Institute of Technology Patna, Bihta, Patna - 801103

Personal web page: https://www.raghavanke.com/

Research Areas

Quantum Optics (Theory and experiment)

Research and Development

Area of Expertise

Research and Development activities & Significant recent contributions

Quantum Optics (Experiment and Theory)

We are currently developing an experimental facility for slow light and quantum memory applications using Electromagnetically Induced Transparency (EIT) phenomenon. Moreover this set up will be upgraded to laser cooled atoms in order to increase the efficiency of Quantum memory.

We also theoretically study the propagation of light pulses in a two dimensional magneto-optical trap (2DMOT) system under Electromagnetically Induced Transparency (EIT) conditions. Slow light generation in cold atomic systems are also studied. Recently we proposed novel theoretical design for the generation of slow light in 2D MOT system.

PhD Students

Sumit Bhushan

Vikash Singh Chauhan

Dixith M

Rohit Kumar

Professional Experience

Post Doc at The University of Nottingham (2013 June to 2013 Dec)
Post Doc at TIFR Mumbai (2009 November to 2013 May)

Awards & Honours

Marie Curie Fellow, European Network
IFRAF French fellowship

Teaching

PH 101(T)
PH102(T)
PH110, B.Tech First year Physics Lab (https://www.raghavanke.com/ph110-b-tech-lab)
NT514
PH 704
PH422
PH709
PH201
PH503
PH 521
PH103, B.Tech First year Physics Theory ( https://www.raghavanke.com/ph103-physics-i-b-tech-first-year)
Weblink for PH 103 Physics Lecture videos (G4,G5,G6) First year B.Tech (2021-2022): https://www.raghavanke.com/ph103-physics-i-2021-2022

Sponsored projects

Title	Principal Investigater	Sponsored by	Duration	Project worth (in lakhs)
Theoretical study on encapsulated Rb atom inside a C-60 cage for Quantum Technology application using Electromagnetically Induced Transparency Protocol The project cited above approved for Core Research Grant to the Science and Engineering Research Board (SERB) for funding for a period of 3 years.	P.I: Dr. Raghavan K Easwaran co-P.I: Nil	Science & Engineering Research Board (SERB)	3 years (Ongoing)	Rs. 26.96 Lakh
"Electromagnetically Induced Transparency and Slow Light in a Two dimensional Magneto Optical Trap (2D MOT)"	P.I: Dr. Raghavan K . Easwaran	SERB, DST, Govt of India	3 years

Publications

Rohit Kumar, Dixith Manchaiah and Raghavan K Easwaran*, Interaction of four level closed loop atomic systems in the presence of two vector beams, Physica Scripta, Volume 98, Number 7 (2023)
Manchaiah, D.; Kumar, R.; Ahmad, M.; Raghavan K Easwaran*,. Normal and anomalous dispersion study on probe light propagation in the presence of structured coupling light using Electromagnetically Induced Transparency protocol DOI: 10.1364/josab.487215 Journal of the Optical Society of America (JOSA B)(2023)
Saumyashree Baral, Raghavan K Easwaran, Jobin Jose *, Aarthi Ganesan, Pranawa C. Deshmukh, Temporal response of atoms trapped in optical dipole trap: A primer on quantum computing speed, Atoms, accepted (2023)
Rohit Kumar, Dixith Manchaiah, Raghavan K Easwaran*,Transmission and dispersion management of room temperature atomic vapor medium of 85Rb using EIT protocol, EPJ Plus, 138, 304 (2023)
Dixith Manchaiah, Rohit Kumar and Raghavan K. Easwaran*, Interplay of polarizations in a cascade EIT system in the presence of vortex coupling light in 87Rb atomic vapor medium, Manuscript reference: NJP-115454.R1, accepted in New Journal of Physics (2023, Jan 4^th) Impact Factor 3.874
Rohit Kumar, Dixith Manchaiah, and Raghavan K. Easwaran*, Theoretical study of a four-level EIT-type system in the presence of structured coupling light for microwave field detection Appl. Opt. 61(36), 10681-10687 (2022).
Dixith Manchaiah, Rohit Kumar, Raghavan K Easwaran*, A Theoretical Analysis on Quantum Memory Parameters in Ultracold 87Rb and 133Cs Alkali Species using EIT Protocol in the Presence of Structured Light,QINP-D-21-00611R1, Quantum Information Processing (2022)
Enhancement of the electromagnetically induced transparency and absorption, Rohit Kumar, Vikas Chauhan, Raghavan K. Easwaran*, Probe 20, 41 (2021).
Measurement of multi-frequency dispersions of Electromagnetically Induced Transparency windows using Spatial Light Modulator in rubidium vapor,Vikas SinghChauhan, DixithManchaiah, PraveenKumar, RohitKumar, SumitBhushan and Raghavan K.Easwaran*, Volume 225, 165707, OPTIK (January 2021)
Enhancement of the electromagnetically induced transparency and absorption signals in 85Rb atomic vapor medium by using the small external magnetic field Vikas SinghChauhan, DixithManchaiah, RohitKumar, and Raghavan K.Easwaran*, Accepted in Journal of the Optical Society of America B (JOSAB) (January 2021)
Vikas S. Chauhan, Rohit Kumar, Dixith M, Praveen Kumar and Raghavan K .Easwaran* Narrowing of electromagnetically induced transperancy by using structured coupling light in 85 Rb vapor medium,Journal of Laser Physics,Volume 30, pp065203, 2020
Vikas S. Chauhan, Dixith M, Sumit Bhushan, Rohit Kumar and Raghavan K .Easwaran*,Theoretical design of Quantum Memory Unit for Under water Quantum Communication Using Electromagnetically Induced Transparency Protocol in ultracold 87 Rb atoms, International Journal of Quantum Information, accepted, July 2020
Vikas S Chauhan, Sumit Bhushan and Raghavan K Easwaran,Magnetic coil design for Two Dimensional Magneto Optical Trap to Realization of Efficient Quantum Memory,AIP Conference Proceedings 2241,020012 (2020).
Sumit Bhushan, Vikas S.Chauhan and Raghavan K. Easwaran, Broadband Quantum Memory Using Electromagnetically Induced Transparency in Atomic Medium, Journal of Modern Optics, Volume 66, Pages 992-997 (2019)
Sumit Bhushan, Vikas S. Chauhan, Raghavan K. Easwaran, Effect of Magnetic Field on a Multi Window Ladder Type Electromagnetically Induced Transparency System of 87Rb Atoms in Vapour Cell,(Accepted on 6th August 2019, Physics Letters A) 2019
Sumit Bhushan, Vikas S.Chauhan and Raghavan K. Easwaran, Ultracold Rydberg atoms for efficient storage of terahertz frequency signals using electromagnetically induced transparency, Physics Letters A,Volume 382, Issue 48, 5 December 2018, Pages 3500-3504
Sumit Bhushan and Raghavan K. Easwaran, A novel theoretical design for generation of slow light in two dimensional magneto optical trap using electromagnetically induced transparency (Applied Optics ,Vol. 56, Issue 13, pp. 3817-3823 (2017)
Gour M. Das, Anil B. Ringne, Venkata R. Dantham, Raghavan K. Easwaran and Ranjit Laha, Numerical investigations on photonic nanojet mediated surface enhanced Raman scattering and fluorescence techniques, Optics Express (Accepted on June 28, 2017).
Towards Ultracold Mixtures of Lithium and Cesium, Asaf Paris-Mandoki, Jonathan Nute, Matt Jones, Raghavan K Easwaran*, Sonali Warriar and Lucia Hackermueller, Bulletin of the American Physical Society, Volume 59, Number 1 (2014)
Dipankar Nath, R Kollengode Easwaran, G Rajalakshmi and C S Unnikrishnan. Quantum-interference enhanced deep sub-Doppler cooling of 39K atoms beyond gray molasses (Phys.Rev. A 88, 053407 (2013))
Dipankar Nath, R Kollengode Easwaran, G Rajalakshmi and C S Unnikrishnan. Accelerated Thermalisation of 39K atoms in a Magnetic Trap with Superimposed Optical Potential J. Phys.B: At. Mol. Opt. Phys. 46 155303 (2013)
C S Unnikrishnan, Vandna Gokhroo, G Rajalakshmi and Raghavan K. Easwaran. A versatile multi-species ultra-cold atoms experiment to study atomic correlations, quantum degeneracy, short-range forces and few-body quantum mechanics, Asian Journal of Physics, 20, No.2 and 3 (2011) 243-25
Vandna Gokhroo, G Rajalakshmi, R Kollengode Easwaran and C S Unnikrishnan. Sub-Doppler deep-cooled bosonic and fermionic isotopes of potassium in a compact 2D+3D MOT set-up J. Phys. B: At. Mol. Opt. Phys, 44 (2011) 115307
R. Kollengode Easwaran, L. Longchambon, P.-E. Pottie, V. Lorent and H. Perrin, and B. M.Garraway. Spectroscopy of a RF-dressed trap. Journal of Physics B, Atomic and molecular physics, 43, 065302 (2010)
.O. Morizot, L. Longchambon, R. Kollengode Easwaran, R. Dubessy, E. Knyazchyan, P.-E.Pottie, V. Lorent and H. Perrin. Influence of the Radio-Frequency source properties on RF- based atom traps. Eur. Phys. J. D 47, 209214 (2008).

Manuscripts under review/preparation

Vikas S. Chauhan, Dixith M, Sumit Bhushan, Rohit Kumar and Raghavan K .Easwaran, Rydberg Electromagnetically Induced Transparency using Blue light in Ultracold 87Rb atoms for Underwater Quantum Communication, Optics Communication (Under Review) 2019
Vikas Singh Chauhan, Dixith M, Praveen Kumar, Rohit Kumar, Sumit Bhushan and Raghavan K Easwaran, Measurement of Dispersive Properties of Multi Window Electromagnetically Induced Transparency in Rubidium Atomic Vapor Medium by Using Spatial Light Modulator, Optik (Under Review) 2019

Conference Proceedings

Sumit Bhushan and Raghavan K. Easwaran, "A compact and versatile design of two dimensional magneto optical trap for slow light experiments", DAE-BRNS National Laser Symposium -25 (NLS-25), CP-04.42, 108 (2016)
Sumit Bhushan and Raghavan K. Easwaran, "Electromagnetically Induced Transparency based Quantum Memory in a Cold Atomic Medium in a 2D-Magneto Optical Trap" National Conference of Atomic and Molecular Physics-XXI (NCAMP), PS-1-4, 60 (2017)

Presentations

Seminar given on 'Ring trap for Ultra cold atoms' Marie Curie Network, Atom Chips workshop,Sicily, Italy
Poster presented in ICAP 2006 International conference , Innsbruck , Austria - Rf-eld dressed ultracold atoms: adiabatic potentials, 2D trapping and vectorial coupling-induced evaporation.
Poster presented in IFRAF Workshop. Ecole Normale Superiere Paris - Influence of the Radio-Frequency source properties on RF-based atom traps.
Poster presented in Doctorants Workshop, Institute Galilee, Villetaneuse, France - Ultra coldatoms conned in 2D dressed potentials.
Poster presented in Indo-French Workshop 2005, Raman Research Institute Bangalore, India- Experimental Realisation of Bose-Einstein Condensates.
Poster presented in ICTP 2011 conference held at Goa, India - Sub-Doppler deep- cooled bosonic and fermionic isotopes of potassium in a compact 2D+-3D MOT set-up
Poster presented in ISAMP Conference, IISER Kolkata, (2012, December), Hybrid trapping of ultracold potassium atoms.
Seminar given at University of Durham, United Kingdom , Ultracold atoms confined in a 2D and hybrid trap (February (2013).
Seminar given at University of Nottingham, United Kingdom, Ultracold atoms confined in a 2D and hybrid trap (January (2013).