Main profile

Ritwick Das

School: 

Physical Sciences

Designation: 

Associate Professor,

School of Physical Sciences

Group leader

Nonlinear Photonics and Lasers Lab

Education: 

1999-2002:  B.Sc. (H) Physics from Hindu College, University of Delhi, India

2002-2004: M.Sc. Physics from I.I.T. Delhi, India

2004-2008: Ph.D. from I.I.T. Delhi, India

2008-2010: Post-doctoral fellow at Optical Parametric Oscillators group, ICFO-The Institute of Photonic Sciences, Barcelona (Spain)

Specialisation: 

Nonlinear Optics, Plasmonics, Topological Photonics

Awards: 

Juan de la Cierva (JdC) Postdoctoral Fellowship by Spanish Ministry of Economy and Competitiveness (2008)

Publications: 

Journals:

• Mukesh K. Shukla and R. Das, “Tamm-plasmon polaritons in one-dimensional photonic quasi-crystals” Optics Letters, vol. 43, pp. 362-365 (2018).
•  M. Chhabra and R. Das, “Probing students’ conceptions at classical - quantum interface,” European Journal of Physics, vol. 39, pp. 025710 (2018).
• M. K Shukla, R. Das, “High-power, single-frequency source in the mid-infrared using a singly-resonant optical parametric oscillator pumped by Yb-fiber laser,” Journal of Selected Topics in Quantum Electronics, vol. 24, 5100206 (2018).
• Partha S. Maji, Mukesh. K. Shukla, R. Das, “Blood component detection based on miniaturized self-referenced hybrid Tamm-plasmon-polariton sensor,” Sensors and Actuators B, vol. 255, pp. 729-734 (2018).
•  S. Kumar and R. Das, “On the tunability of quality-factor for optical Tamm plasmon modes,” Journal of Optics vol. 19, pp. 095001 (2017).
• S. Kumar, M. K. Shukla, P. S. Maji and R. Das, “Self-referenced refractive index sensing with hybrid-Tamm-plasmon-polariton modes in sub-wavelength analyte layers,” Journal of Physics D: Applied Physics, in press (2017).
• P. S. Maji, R Das, “Hybrid-Tamm-Plasmon-Polariton Based Self-Reference Temperature Sensor,” Journal of Lightwave Technology, vol. 35 (14), pp. 2833-2839 (2017).
• Samir Kumar, Partha Sona Maji, Ritwick Das, “Tamm-plasmon resonance based temperature sensor in a Ta₂O₅/SiO₂ based distributed Bragg reflector,” Sensors and Actuators A: Physical, vol. 260, pp. 10-15 (2017).
• S. Kumar, K.V. Anil Kumar, S.M. Dharmaprakash, and R. Das, “Phase-dependent ultrafast third-order optical nonlinearities in metallophthalocyanine thin films,” Journal of Applied Physics, vol. 120, pp. 123104 (2016).
• M. K. Shukla, P.S. Maji and R. Das “Yb-fiber laser pumped high-power, broadly tunable, single-frequency red source based on a singly resonant optical parametric oscillator,” Optics Letters, vol. 41, pp. 3033-3036 (2016).
• M. K Shukla, S. Kumar, R. Das, “Single-pass, efficient type-I phase-matched frequency-doubling of high-power ultrashort-pulse Yb-fiber laser using LiB₃O₅”, Applied Physics B, vol. 122, pp. 114 (2016).
• M. Chhabra, R. Das, “Quantum mechanical wavefunction: Visualization at undergraduate level,” European Journal of Physics, vol. 38, pp. 015404 (2016).
• K.V. Anil Kumar, S. Kumar, SM Dharmaprakash, and Ritwick Das, “Impact of α→ β Transition in the Ultrafast High-Order Nonlinear Optical Properties of Metal-Free Phthalocyanine Thin Films” J. Physical Chemistry C, vol. 120, pp. 6733–6740 (2016).
• M. K. Shukla, S. Kumar, R. Das, “Single-pass, multi-watt second-harmonic-generation in congruent and stoichiometric LiTaO₃” IEEE Photonics Technology Letters, Vol. 27, pp. 1379-1382 (2015).
• A. Singh, S. Kumar, R. Das and P. K. Sahoo “Defect-assisted saturable absorption characteristics in Mn doped ZnO Nano-rods,” RSC Advances, vol. 5, pp. 88767–88772 (2015).
• A. Garai, S. Kumar, W. Sinha, C. S. Purohit, Ritwick Das and Sanjib Kar, “A comparative study of optical nonlinearities of trans-A2B-corroles in solution and in aggregated state,” RSC Advances, Vol. 5, pp. 28643–28651 (2015). DOI: 10.1039/c5ra03568f
• Ritwick Das, T. Srivastava, Rajan Jha, “On the performance of Tamm-plasmon and surface-plasmon hybrid-mode refractive-index sensor in metallo-dielectric heterostructure configuration,” Sensors & Actuators: B. Chemical, Vol. 206, pp. 443-448 (2015).
• T. Srivastava, Ritwick Das, P. Padhy, R. Jha, “THz mode‑coupling in photonic‑crystal–surface‑plasmon‑coupled waveguides,” Applied Physics B, vol. 118, pp. 387-392 (2015). DOI 10.1007/s00340-014-5996-6.
• Awanish Pandey and Ritwick Das, “Distributed-Bragg-reflector assisted tailoring of extraordinary transmission spectrum for sub-wavelength hole-array,” Plasmonics, Vol. 9, pp. 1315-1321 (2014).
• Ritwick Das, “Optical Tamm mode based refractometer in all-dielectric configuration,” Photonics and Nanostructures: Fundamental and Applications, Vol. 12, pp. 252-258 (2014).
• Ritwick Das and M. K. Shukla, “Measurement of nonlinear refractive index in open-aperture Z-scan experiments,” Pramana Journal of Physics, in press (2014). DOI 10.1007/s12043-014-0819-1
• Ritwick Das, T. Srivastava, and Rajan Jha, “Guided-mode Analysis of Tamm-Plasmon Polariton at Metal-Heterostructure Dielectric Interface,” IEEE/OSA Journal of Lightwave Technology, Vol. 32, pp. 1221-1227 (2014).
• Ritwick Das, T. Srivastava and Rajan Jha, “Tamm-plasmon and surface plasmon hybrid-mode based refractometry in photonic bandgap structures,” Optics Letters, Vol. 39, pp. 896-899 (2014).
• T. Srivastava, Ritwick Das, Rajan Jha, “Mode-coupling between surface plasmon modes and bandgap-guided modes: A comprehensive study and applications,” IEEE/OSA Journal of Lightwave Technology, Vol. 31, pp. 3518-6524 (2013).
• T. Srivastava, Ritwick Das, Rajan Jha, “Highly sensitive plasmonic temperature sensor based on photonic crystal surface plasmon waveguide,” Plasmonics, Vol. 8, pp. 515-521 (2013).
• T. Srivastava, Ritwick Das, Rajan Jha, “On the high performance of channel photonic crystal waveguide comprising different plasmonic active metals,” Applied Physics B Vol. 108, pp.629-634 (2012).
• T. Srivastava, Rajan Jha, Ritwick Das, “High-Performance Bimetallic SPR sensor based on Photonic Crystal-Waveguides,” IEEE Photonics Technology Letters, vol. 23, pp. 1448-1450 (2011).
• T. Srivastava, Ritwick Das, Rajan Jha, “Highly accurate and sensitive surface plasmon resonance sensor based on channel photonic crystal waveguides,” Sensors and Actuators B, vol. 157, pp. 246-252 (2011).
• S. Chaitanya Kumar, Ritwick Das, G. K. Samanta, and M. Ebrahim-Zadeh, “Optimally-out-coupled, 17.5 W, Yb-fiber-laser-pumped continuous-wave, MgO:PPLN optical parametric oscillator”, Applied Physics B, vol. 102, pp. 31-35 (2011).
• Triranjita Srivastava, Ritwick Das and Rajan Jha “Design considerations and propagation characteristics of channel Bragg-plasmon-coupled-waveguides,” Applied Physics Letters, vol. 97, pp. 213104 (2010).
• Ritwick Das, S. Chaitanya Kumar, G. K. Samanta, and M. Ebrahim-Zadeh, “Broadband, high-power, continuous-wave, mid-infrared source using extended phase-matching bandwidth in MgO:PPLN”, Optics Letters, vol. 34, pp. 3836-3838 (2009).
• Ritwick Das, “Ultra-broadband optical parametric amplification by tailoring the group-velocity-dispersion of Bragg reflection waveguides”, Journal of Physics D: Applied Physics, vol. 42, pp. 235106 (2009).
• Ritwick Das and K. Thyagarajan, “Broadband mid-infrared generation by difference-frequency-generation in strongly dispersive Bragg reflection waveguides”, Journal of Applied Physics, vol. 106, pp. 093101 (2009).
• Ritwick Das and K. Thyagarajan, “Ultra-broadband mid-infrared generation using non-degenerate difference-frequency-generation in group-velocity-dispersion tailored Bragg reflection waveguides”, Applied Optics, vol. 48, pp. 5678-5682 (2009).
• Ritwick Das and Rajan Jha, “On the modal characteristics of surface-plasmon polaritons at a metal-Bragg interface at optical frequencies”, Applied Optics, vol. 48, 4904-4908 (2009).
• Ritwick Das and K. Thyagarajan, “Strong dispersive features of dual Bragg cladding waveguides using higher-order mode-coupling mechanism”, Journal of Optics A: Pure and Applied Optics, vol. 11, pp. 105410- (2009).
• G.K. Samanta, S. Chaitanya Kumar, Ritwick Das, and M. Ebrahim-Zadeh, “Continuous-wave optical parametric oscillator pumped by a fiber laser green source at 532 nm”, Optics Letters, vol. 34, pp. 2255-2257 (2009). *Also selected/listed for Virtual Journal of Ultrafast Science (Published by AIP), September (2009), scitation.aip.org/ultrafast/
• Krishna Thyagarajan, Ritwick Das, Olivier Alibart, Marc de Micheli, Daniel B. Owstrosky, Sébastien Tanzilli “Increased pump acceptance bandwidth in spontaneous parametric down conversion process using Bragg reflection waveguides”, Optics Express, vol. 16, pp. 3577-3582 (2008).
• Ritwick Das and K. Thyagarajan, “Broadband parametric amplification in Bragg reflection waveguide”, Journal of Modern Optics, vol. 55, pp. 273-279 (2008).
• Ritwick Das and K. Thyagarajan, “Broadening of the phase-matching bandwidth in quasi-phase matched second harmonic generation using GaN based Bragg reflection waveguide”, Optics Letters, vol. 32, pp. 3128-3130 (2007).
• Ritwick Das and K. Thyagarajan, “A High Efficiency Scheme for Phase-Matched Second Harmonic Generation in GaN Based Bragg Reflector Waveguide”, IEEE Photonics Technology Letters, vol. 19, pp. 1526-1528 (2007).
• Ritwick Das and K. Thyagarajan, “SHG in Bragg reflection waveguides for enhanced bandwidth applications”, Optics Communications, vol. 270, pp. 79-84 (2007).
• Ritwick Das, and K. Thyagarajan, “Anomalous behaviour in Bragg reflection waveguide”, Optics Communications, vol. 273, pp. 84-88 (2007).

Conferences:

• Mukesh K. Shukla, and R. Das, “High Power, tunable, Mid-IR generation with singly resonant optical parametric oscillator,” 2017 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Singapore, Singapore, pp. 1-2, 2017.
•  Mukesh K. Shukla, P. S. Maji, and R. Das, “Tamm-plasmon-polaritons in photonic quasicrystals,” 2017 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Singapore, Singapore, pp. 1-2, 2017.
• S. Kumar, Mukesh K. Shukla, P. S. Maji and R. Das, “Refractive index sensor based on hybrid-Tamm plasmon-polariton and cavity mode,” 2017 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Singapore, Singapore, 2017, pp. 1-2.
• S. Kumar and R. Das, "Refractive Index Sensing With 1D Photonic Crystal," in Frontiers in Optics 2017, OSA Technical Digest (online) (Optical Society of America, 2017), paper LTh2F.3.
• S. Kumar, M. K. Shukla, and R. Das, "On the Coupling Efficiency of Tamm Plasmon Polaritons," in Frontiers in Optics 2017, OSA Technical Digest (online) (Optical Society of America, 2017), paper JW3A.99.
• M. K. Shukla and R. Das, "Tamm plasmon polaritons in aperiodic metal deposited Bragg reflectors," in Frontiers in Optics 2017, OSA Technical Digest (online) (Optical Society of America, 2017), paper JTu3A.115.
• S. Kumar and R. Das, "Quality-Factor Enhancement in Optical Tamm Plasmon Modes," in 13th International Conference on Fiber Optics and Photonics, OSA Technical Digest (online) (Optical Society of America, 2016), paper Th2D.4.
• M. K. Shukla, P. S. Maji, and R. Das, "Performance of β-BaB₂O₄and BiB₃O₆ as anintra-cavity frequency-doubling element insingly-resonant optical parametric oscillators," in 13th International Conference on Fiber Optics and Photonics, OSA Technical Digest (online) (Optical Society of America, 2016), paper W3A.41.
• P. S. Maji and R. Das, "Broadband FOPA based on single ZDW ultra-flat near-zero dispersion PCF," in 13th International Conference on Fiber Optics and Photonics, OSA Technical Digest (online) (Optical Society of America, 2016), paper W3A.57.
• M. K. Shukla, P. Maji, and R. Das, "On the performance of β-BaB2O4 and BiB3O6 as an intra-cavity frequency-doubling element in optical parametric oscillators," in Frontiers in Optics 2016, OSA Technical Digest (online) (Optical Society of America, 2016), paper JTh2A.110.
• S. Kumar, K. V. A. Kumar, S. Dharmaprakash, and R. Das, "Ultrafast Optical Nonlinearities in 2, 9, 16, 23-Tetra-tert-butyl-29H, 31H-Phthalocyanine Thin Films," in Advanced Photonics 2016 (IPR, NOMA, Sensors, Networks, SPPCom, SOF), OSA Technical Digest (online) (Optical Society of America, 2016), paper NoW2D.1.
•  M. K. Shukla, P. S. Maji, and R. Das, "2.6W, single-frequency, broadly tunable red-source based on Yb-fiber laser," in Conference on Lasers and Electro-Optics, OSA Technical Digest (online) (Optical Society of America, 2016), paper JTu5A.58.
• S. Kumar and R. Das K. V. A. Kumar, and S. Dharmaprakash Femtosecond nonlinear optical properties of as grown and annealed Phthalocyanines thin films Recent Advances in Photonics (WRAP), 2015 Workshop on (2015) DOI: 10.1109/WRAP.2015.7805972.
• S. Kumar and R. Das, "Tamm-plasmon States in Broadband Dielectric-coated Mirror," in Frontiers in Optics 2015, OSA Technical Digest (online) (Optical Society of America, 2015), paper FW5C.8.
• Mukesh K. Shukla, Samir Kumar and Ritwick Das, “High-power, single-frequency, single-pass second-harmonic-generation by optimally focused Yb-fiber laser” Proc. of Advanced Solid State Lasers (ASSL) 2014, Shanghai, China, Nov. 2014.
• Mukesh K. Shukla, Samir Kumar and Ritwick Das, “High-power frequency-doubled Yb-fiber laser”, Proc. of 12^th International Conference on Optoelectronics, Fiber Optics and Photonics: PHOTONICS 2014, IIT Kharagpur, India, Dec. 2014
• Ritwick Das, R. Jha, T. Srivastava, “Accurate refractive-index sensing with Tamm-plasmon and surface-plasmon based hybrid configurations”, Proc. of 12^th International Conference on Optoelectronics, Fiber Optics and Photonics: PHOTONICS 2014, IIT Kharagpur, India, Dec. 2014
• Ritwick Das, “Refractometry using optical Tamm modes,” Proc. of International Conference on Optics and Opto–electronics (ICOL) 2014 held at IRDE, Dehradun, India, Mar. 2014.
• Mukesh K. Shukla, Samir Kumar and Ritwick Das, “Saturation effects in high-power, continuous-wave, frequency doubling of Yb-fiber laser using MgO:cPPLT,” Proc. of International Conference on Optics and Opto–electronics (ICOL) 2014 held at IRDE, Dehradun, India, Mar. 2014.
• Ritwick Das and Mukesh K. Shukla, “Measurement of nonlinear refractive index in open-aperture Z-scan Experiments,” Workshop on Recent Advances in Photonics (WRAP), IIT Delhi, Dec. 2013.
• S. Bharadwaj, P. K. Maharana, Ritwick Das and R. Jha, “Effect of chalcogenide glass and plasmonic metal on electric field enhancement in surface plasmon resonance sensor,” Proc. of 11^th International Conference on Optoelectronics, Fiber Optics and Photonics: PHOTONICS 2012, IIT Chennai, India, Dec. 2012.
• Ritwick Das, R. Jha, T. Srivastava , “Avoided-crossings in dispersion properties of photonic-crystal-surface-plasmon-waveguides,” Proc. of 11^th International Conference on Optoelectronics, Fiber Optics and Photonics: PHOTONICS 2012, IIT Chennai, India, Dec. 2012.
• Ritwick Das, R. Jha, T. Srivastava, “Resonant mode-coupling at anti-crossing points in THz regime,” XXXVI Optical Society of India Symposium on Frontiers in Optics and Photonics at IIT Delhi, Dec. 2011.
• Ritwick Das, R. Jha, T. Srivastava, “Channeled Bragg-plasmon coupled waveguide”, Proc. of 10^th International Conference on Optoelectronics, Fiber Optics and Photonics: PHOTONICS 2010, Guwahati, India, Dec. 2010.
• Rajan Jha, Ritwick Das, T. Srivastava, “Photonic crystal waveguide based SPR sensor” Proc. of 10^th International Conference on Fiber Optics and Photonics: PHOTONICS 2010, at IIT Guwahati, India, Dec. 2010 (Post-deadline paper)
• S. Chaitanya Kumar, Ritwick Das, G. K. Samanta and M. Ebrahim-Zadeh, “High-Power, broadband, continuous-Wave, mid-infrared optical parametric oscillator based on MgO:PPLN,” Oral presentation, Conference on Lasers and Electro-Optics (CLEO-2010), San Jose, U.S.A., May 2010, paper control no. 750).
• S. Chaitanya Kumar, Ritwick Das, G. K. Samanta and M. Ebrahim-Zadeh, “Stable, 17.5 W, optimally-output-coupled, Yb-fiber-pumped mid-infrared optical parametric oscillator,” Oral presentation, Conference on Lasers and Electro-Optics (CLEO-2010), San Jose, U.S.A., May 2010, paper control no. 704).
• S. Chaitanya Kumar, Ritwick Das, G. K. Samanta and M. Ebrahim-Zadeh, “Optimally-output-coupled, 17.5 W, Yb-fiber-laser-pumped continuous-wave optical parametric oscillator,” Post-deadline presentation, Proc. 1^st European Optical Society Topical Meetings on Lasers 2009 (September), Capri, Italy.
• Ritwick Das, G. K. Samanta, S. Chaitanya Kumar and M. Ebrahim-Zadeh, “32% efficient, continuous wave, Yb-fiber laser pumped single pass second-harmonic-generation in MgO:sPPLT,” Proc. of Conference on Lasers and Electro-optics (CLEO-Europe), Munich, Germany, June 2009, paper no. 385.
• S. Chaitanya Kumar, Ritwick Das, G. K. Samanta and M. Ebrahim-Zadeh, “16.6 W, Continuous-Wave, Yb-fiber-Laser-Pumped, Singly-Resonant Optical Parametric Oscillator based on MgO:PPLN,” Proc. of Conference on Lasers and Electro-optics (CLEO-Europe), Munich, Germany, June 2009, paper no. 1260.
• G. K. Samanta, S. Chaitanya Kumar, Ritwick Das and M. Ebrahim-Zadeh, “Stable, Continuous-Wave, Single-frequency, Singly Resonant Optical Parametric Oscillator Pumped in the Green by Frequency-Doubled Fiber Laser,” Proc. of Conference on Lasers and Electro-optics (CLEO-Europe), Munich, Germany, June 2009, paper no. 463.
• S. Chaitanya Kumar, Ritwick Das, G. K. Samanta and M. Ebrahim-Zadeh, “Generation of 16.6 W of tunable mid-infrared radiation with an Yb-fiber-laser-pumped, continuous-wave, singly-resonant optical parametric oscillator,” Proc. of Conference on Middle-infrared coherent sources (MICS-2009), Trouville, France, June 8-12.

Responsibilities: 

# Faculty-in-charge - Estate Management and Works

# Chairperson - Institute Works Committee

# Member - Post-Graduate-Committee for the School (PGCS)

Research: 

The field of optics blended with modern material fabrication technologies has given rise to the field of Photonics.  This includes nano-photonics, quantum optics, bio-photonics, nonlinear optics etc. which has substantially extended the reach of optics to many other disciplines of Science and Technology. The invention of Laser by Theodore Maiman at Hughes Labs in the year 1960 followed by rapid progress in Laser Technology has provided a strong impetus to the field of Photonics. Today, Photonics is touching the human life from every possible direction and the applications range from Telecommunications to Medicine, from Military Warfare to Entertainment Industry.

We, at the School of Physical Sciences at NISER, are focusing on Nonlinear Photonics which mainly include generation of high-power radiations at wavelengths different from the conventional Laser sources and are tunable across a band of wavelengths or frequencies. The underlying physical processes include Second-Harmonic-Generation (SHG), Third-Harmonic-Generation (THG), Optical-Parametric-Generation/Oscillation (OPG/OPO), Four-Wave-Mixing (FWM) etc. in the bulk as well as waveguiding geometries. The field of Nano-Photonics and Plasmonics is another area where we are laying significant emphasis. We are theoretically and experimentally investigating the surface optical properties/surface states of periodic and aperiodic photonic lattices in order to ascertain topological phases in such systems. By carrying out such investigations, we aim to reduce the design as well as fabrication tolerances in modern-generation photonic/optical systems for applications in spectroscopy/sensing/communications. Our laboartory posses variety of fiber lasers which includes single-frequency, continuous-wave 40.0 W Yb-fiber laser and 20.0 W green fiber laser. Also, we have added high-pulse energy Yb-fiber laser (>30 microjoule) with ultrashort (< 300 femtosecond) pulse-width to be used for various nonlinear optical studies.

Teaching: 

P203: Electronics

P204: Electromagnetic Theory 1

P456: Nonlinear optics and Lasers

P603: Electromagnetic Theory (Pre-doc course)

P443/444: Spectroscopy and Lasers Lab

 

Contacts: 

Dr. Ritwick Das

FC-015, School of Physical Sciences,

National Institute of Science Education and Research,

P.O. Bhimpur-Padanpur, Via - Jatni,

Bhubaneswar - 752050

Email: ritwick.das@niser.ac.in

Telephone: +91-674-2494251

Phone No.: 

+91 674-2494251

Room No.: 

015 FC