Dr Vishwa Pal
Dr. Vishwa Pal
Associate Professor
vishwa.pal@iitrpr.ac.in
+91-1881-232472
https://iitrpr.ac.in/laserlab
A-315, Super Academic Block

Biography

Dr. Vishwa Pal is an Associate Professor in the Department of Physics at the Indian Institute of Technology (IIT) Ropar, Punjab, India. He earned his PhD degree in 2014 from the School of Physical Sciences, Jawaharlal Nehru University (JNU), New Delhi, India. As part of his doctoral research, he conducted a portion of his work at the CNRS Laboratoire Aimé Cotton, Orsay, France, under the Indo-French collaborative framework. His Ph.D. research focused on the investigation of semiconductor laser systems, specifically exploring noise correlations and dynamical control using delayed optical feedback. Following his Ph.D., Dr. Pal was awarded the prestigious PBC Fellowship for Outstanding Postdoctoral Researchers by the Council for Higher Education of Israel. He joined the research group of Prof. Nir Davidson and Prof. Asher A. Friesem at the Weizmann Institute of Science, Israel. His postdoctoral research focused on phase-locking large arrays of lasers and utilizing them to explore topological effects, simulate spin systems, and solve computationally hard problems. Additionally, he contributed to industrial laser beam shaping applications in collaboration with Israeli industry partners. In 2018, Dr. Pal joined CREOL, The College of Optics and Photonics, in Florida, USA, as a Research Scientist. There, he worked on the synthesis of non-diffracting optical beams in free space by leveraging space-time correlations. In the same year, he was awarded the Marie Sklodowska-Curie Actions Individual Fellowship by the European Commission.


Area of Research

High-power Lasers, Structured light & Topological photonics, Quantum-inspired computing, Quantum light sources, Quantum imaging


Education

  • Ph.D., Jawaharlal Nehru University, New Delhi, India, 2014. (Part of the PhD work is done at CNRS Laboratoire Aime Cotton (LAC), Orsay, France)
  • M.Sc., University of Lucknow, Lucknow, India, 2006
  • B.Sc., M.J.P. Rohilkhand University, Bareilly, India, 2004


Work Experience

  • Associate Professor, Department of Physics, IIT Ropar, India (June 2025 - present)
  • Assistant Professor, Department of Physics, IIT Ropar, Punjab, India (May 2018 - May 2025)
  • Research Scientist, CREOL, The College of Optics & Photonics, UCF, Orlando, Florida, USA (March 2018 - April 2018)
  • Research Staff Intern, Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel (April 2017 - February 2018)
  • Postdoctoral Research Fellow, Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel (April 2013 - March 2017)


Other Information

For more details -

Google Scholar: https://scholar.google.co.in/citations?user=4TfBoFEAAAAJ&hl=en 

Orcid: https://orcid.org/0000-0002-8395-2060 

Research

  • My research focuses on the following areas:


    1) High-power from phase-locked lasers:

    Lasers are the key components for many branches of science and technology and also serve as fundamental tools for studying other systems. Particularly, lasers with very high power and ideal beam quality have a large potential in scientific research, material processing, communication, medical, industrial and defense applications, and research in this direction has been in progress ever since the invention of lasers. High-power lasers often have beam quality, stability, and heat dissipation inferior to those of lower-power lasers. The phase locking of several lasers is a promising approach to synthesize high-power optical sources with ideal beam quality. However, the phase locking of many lasers is a challenging task, since it requires, at the very least, a common lasing frequency to all the lasers, a prospect that vanishes exponentially with the number of lasers. Our group activities are focused on to find solutions to overcome such limitations, and thereby to push the upper limit on the number of lasers that can be phase locked, and hence to increase the output powers while maintaining the ideal beam quality.

    References:

    1. S. Mahler, M. L. Goh, C. Tradonsky, A. A. Friesem, and N. Daivdson, "Improved phase locking of laser arrays with nonlinear coupling," Physical Review Letters 124, 133901 (2020).
    2. M. Nixon, E. Ronen, A. A. Friesem, and N. Davidson, "Observing geometric frustration with thousands of coupled lasers," Physical Review Letters 110, 184102 (2013).
    3. V. Pal, S. Mahler, C. Tradonsky, A. A. Friesem, and N. Davidson, "Rapid fair sampling of the XY spin Hamiltonian with a laser simulator," Physical Review Research 2, 033008 (2020).
    4. C. Tradonsky, V. Pal, R. Chriki, N. Davidson, and A. A. Friesem, "Talbot diffraction and Fourier filtering for phase locking an array of lasers," Applied Optics 56, A126 (2017).
    5. C. Tradonsky, M. Nixon, E. Ronen, V. Pal, R. Chriki, A. A. Friesem, and N. Davidson, "Conversion of out-of-phase to in-phase order in coupled laser arrays with second harmonics," Photonics Research 3, 77 (2015).
    6. S. Karuseichyk, V. Pal, S. Sahoo, G. Beaudoin, I. Sagnes, and F. Bretenaker, "Investigation of noise correlations in the phase-locked class-A VECSEL," Optics Express 31, 41713 (2023).
    7. V. Dev, A. N. K. Reddy, and V. Pal, "Generating high-energy densities by side lobe suppression in the far-field of phase locked lasers," Journal of Optical Society of America B 39, 2254 (2022).


    3) Quantum-inspired computing with lasers:

    Optimization plays a crucial role in making decisions and in analyzing systems. Specifically, it deals with finding the best solution from among many feasible solutions (for example, traveling salesman problem). Such problems are ubiquitous across social science, biology, chemistry, physics, engineering, computer science, big data and artificial intelligence. Many such problems are classified as computationally hard problems (belong to non-deterministic polynomial time (NP)-hard or NP-complete complexity classes), and solving them efficiently has been beyond the reach of modern computers. Solving them efficiently and rapidly with physical systems has become an emrging field of research. Physical optimization relies on finding the ground state of a complex system as a physical analogy to the optimization problem. 

    There has been significant interest in building efficient solvers that are based on physical systems, and recently some of have realized. These include solvers that invlove coupled lasers, Bose-Einstein condenstae (BEC) polaritons and optical parametric oscillators. Particularly, our activities are focused on to build a rapid and efficient solver based on coupled lasers to solve these class of problems.

    References:

      1. V. Pal, S. Mahler, C. Tradonsky, A. A. Friesem, and N. Davidson, "Rapid fair sampling of the XY spin Hamiltonian with a laser simulator," Physical Review Research 2, 033008 (2020).
      2. C. Tradonsky, I. Gershenzon, V. Pal, R. Chriki, A. A. Friesem, O. Raz, and N. Davidson, "Rapid laser solver for the phase retrieval problem," Science Advances 5, eaax4530 (2019).
      3. V. Pal, C. Tradonsky, R. Chriki, A. A. Friesem, and N. Davidson, "Observing dissipative topological defects with coupled lasers," Physical Review Letters 119, 013902 (2017).
      4. M. Nixon, E. Ronen, A. A. Friesem, and N. Davidson, "Observing geometric frustration with thousands of coupled lasers," Physical Review Letters 110, 184102 (2013).
      5. M. Nixon, O. Katz, E. Small, Y. Bromberg, A. A. Friesem, Y. Silberberg, and N. Davidson, "Real-time wavefront shaping through scattering media by all optical feedback," Nature Photonics 7, 919 (2013).
      6. S. Karuseichyk, V. Pal, S. Sahoo, G. Beaudoin, I. Sagnes, and F. Bretenaker, "Investigation of noise correlations in the phase-locked class-A VECSEL," Optics Express 31, 41713 (2023).


    3) Laser beam shaping / Structured light:

    Generation of optical fields with complex spatial and temporal distribution has attracted considerable interest due to numerous applications, both in fundamental science as well as engineering applications, in various fields. Typically, the output from a laser source consists of a Gaussian distribution, which is undesirable for many applications. However, in recent years, it has become possible to control the distribution of light in the spatial and temporal domain, which allows to produce spatially variant polarization states, exotic phase structures and tailored intensity patterns. The structured light with a daisy-petal-like intensity pattern was used to probe planer and non-planner surface displacements at picometer scale resolution. This has opened a route to measure weak radiation pressure and optical manipulation of liquid/solid interface that possess the potentials for applications in opto-fluidics, microfluidics, and gravitational waves detection. A synthetic chiral structured light was shown to efficiently control chiral light-matter interaction, and provides the possibility for drug development. The optical vortices were exploited to probe magnetism in materials. The well- known Rayleigh limit was sown to overcome by structured illumination, and thus allowed to achieve super- resolution in the imaging techniques. Very recently, compressive three-dimensional super-resolution microscopy with speckle-saturated fluorescence excitation was demonstrated. Further, polarization based speckle-field digital holograpic microscopy was also shown to probe features in the biological tissues with enhanced spatial resolution and controlled coherent noise reduction. Moreover, structured light is also deployed in many other fields, such as optical metrology, optical communications, optical trapping and manipulations, and atomtronic devices.

    Our group activities are focused on controlled laser beam shaping involving intra- and extra- laser cavity configurations. The main focus is to acheive the high quality structured light with high powers, extended depth of focus, and applicable to a wide spectral range.

    References:

      1. A. N. Jena, T. M. Hayward, A. Kumari, A. Majumder, J. Devara, R. Menon, K. P. Singh, and V. Pal, "Extended depth-of-focus femtosecond laser pulses for flexible micromachining," Optics Letters (2025) [In press].
      2. A. Kumari, V. Dev, and V. Pal, "Abrupt autofocusing of circular Airy derivative beams in complex media," Optics & Laser Technology 183, 112319 (2025).
      3. S. Karuseichyk, I. Audoin, V. Pal, and F. Bretenaker, "Non-symmetrical vortex beam shaping in VECSEL laser arrays," Photonics Research 13, 1600 (2025).
      4. A. Kumari, V. dev, T. M. Hayward, R. Menon, and V. Pal, "Generating optical vortex needle beams with a flat diffractive lens," Journal of Applied Physics 136, 113105 (2024).
      5. V. Dev, and V. Pal, "Probing topological charge of discrete vortices," Physical Review Applied 20, 034071 (2023).
      6. V. Dev, A. N. K. Reddy, A. V. Ustinov, S. N. Khonina, and V. Pal, "Auto-focusing and self-healing properties of aberration laser beams in a turbulent media," Physical Review Applied 16, 014061 (2021).
      7. C. Tradonsky, S. Mahler, G. Cao, V. Pal, R. Chriki, A. A. Friesem, and N. Davidson, "High-resolution digital spatial control of highly multimode laser," Optica 8, 880 (2021).


    4) Topological photonics:

    The topological photonics has emerged a new exciting field of research, where the application of topology is creating a range of new opportunities throughout the photonics. The topology has emerged as another degree of freedom, which opens a new door for the discovery of fundamentally new states of light and possible revolutionary applications. For example, potential practical applications of topological photonics include photonic circuitry that is less dependent on isolators and slow light that is insensitive to disorder. Few more demonstrations of topological effects were realized in photonic crystals, coupled resonators, waveguides, metamaterials and quasicrystals. Our group activities are focused on to investigate topological effects in a non-Hermitian system of coupled lasers.

    References:

      1. V. Pal, C. Tradonsky, R. Chriki, A. A. Friesem, and N. Davidson, "Observing dissipative topological defects with coupled lasers," Physical Review Letters 119, 013902 (2017).
      2. A laser model for cosmology, Nature 549, 163 (2017).
      3. Cooperating lasers make topological defects, APS focus story -- https://physics.aps.org/articles/v10/79
      4. S. Mahler, V. Pal, C. Tradonsky, R. Chriki, A. A. Friesem, and N. Davidson, "Dynamics of disspative topological defects in coupled phase oscillators," Journal of Physics B: At. Mol. Opt. Phys. 52, 205401 (2019).
      5. L. Lu, J. D. Joannopoulos, and M. Soljacic, "Topological photonics," Nature Photonics 8, 821 (2014).


    5) Quantum light sources and Quantum imaging (under National Quantum Mission):

    Our objective is to develop novel laser sources capable of generating entangled photons with tunable quantum correlations, aimed at enabling quantum-enhanced imaging that remains robust in noisy and scattering environments. This represents a dynamic and rapidly evolving field with significant potential for advancing quantum technologies.

    References:

      1. O. Lib, and Y. Bromberg, "Quantum light in complex media and its applications", Nature Physics 18, 986 (2022).  
      2. O. Lib, and Y. Bromberg, "Spatially entangled Airy photons," Optics Letters 45, 1399 (2020).



    Group Member

    Present members:

    Ph.D. students:  
    • Anita Kumari (August 2021-present)
    • Love Kumar Sharma (January 2022-present)
    • Rajneesh Fulara (January 2023-present)
    • Adityanarayan Jena (August 2023-present)

    Master students:    

    • Ayushi Sood  (August 2024-present)
    • Bhanu Pratap Singh Rathore (August 2024 - present) 



    Former members:


    PhD students:

    • Vasu Dev  (August 2018-June 2023); Thesis title: Generation and characterization of spatially controlled structured light with exotic propagation properties. [Presently working as a postdoctoral fellow at Center for Quantum Technologies, National University of Singapore (NUS), Singapore.]

    Master and summer students:

    • Rishabh Sahoo (Summer Intern) (Pursuing B.Tech in Engineering Physics, IIT Guwahati)
    • Sakshi Raheja (M.Sc. student)
    • Parmiti Gupta (Summer Intern, B.Tech-EP IIT Guwahati) (Pursuing master program at Abbe School of Photonics, Jena, Germany)
    • Sahil Sahoo (M.Sc. student) (Pursuing PhD at Ariel University, Israel)
    • Vivek (M.Sc. student) (Teaching staff at Akash Institute, Delhi)
    • Manisha Rajpurohit (M.Sc. student)
    • Pragya Sharma (M.Sc. student) (Pursuing integrated PhD program in the framework of Max Planck School of Photonics at the Friedrich-Alexander-Universität Erlangen-Nürnberg, Bavaria, Germany)
    • Sachleen Singh (M.Sc. student) (Pursuing PhD in the group of Prof. Andrew Forbes at University of the Witwatersrand, Johannesburg, South Africa)
    • Aishwarya CB (Summer intern)
    • Vidisha Rao (M.Sc. student)
    • Ishmeet Singh Chawla (MSc. student) (Pursuing PhD at IIT Kanpur)
    • Sobhit Gupta (M.Sc. student)
    • Karmender (M.Sc. student)




    Lab Facility


    Publications

    1. Abrupt autofocusing of circular Airy derivative beams in complex media
    Anita Kumari, Vasu Dev, Dr. Vishwa Pal
    Optics & Laser Technology 183, 112319 (2025)

    2. Non-symmetrical vortex beam shaping in VECSEL laser arrays
    Sopfy Karuseichyk, Ilan Audoin, Dr. Vishwa Pal, Fabien Bretenaker
    Photonics Research 6, 1600-1610 (2025)

    3. Extended depth-of-focus femtosecond laser pulses for flexible micromachining
    Aditya N. Jena, Tina M. Hayward, Anita Kumari, Apratim Majumder, Jayant Devara, Rajesh Menon, Kamal P. Singh, Dr. Vishwa Pal
    Optics Letters 50, 4670 (2025)
    1. The Effect of a Parabolic Apodizer on Improving the Imaging of Optical Systems with Coma and Astigmatism Aberrations
    Andra Naresh Kumar Reddy, Vasu Dev, Dr. Vishwa Pal, Rashid A. Ganeev, 
    Photonics 11, 14 (2024)

    2. Generating optical vortex needle beams with a flat diffractive lens
    Anita Kumari, Vasu Dev, Tina M. Hayward, Rajesh Menon, Dr. Vishwa Pal
    Journal of Applied Physics 136, 113105 (2024)

    1. Autofocusing and self-healing of partially blocked circular Airy derivative beams
    Anita Kumari, Vasu Dev, Dr. Vishwa Pal
    Optics & Laser Technology 168, 109837 (2023)

    2. Probing topological charge of discrete vortices
    Vasu Dev, Dr. Vishwa Pal
    Physical Review Applied  20, 034071 (2023)

    3. Investigation of noise correlations in the phase-locked class-A VECSEL array
    Sopfy Karuseichyk, Dr. Vishwa Pal, Sahil Sahoo, Gregoire Beaudoin, Isabelle Sagnes, Fabien Bretenaker
    Optics Express  31, 41713 (2023)
    1. Phase locking of lasers with Gaussian coupling
    Andra Naresh Kumar Reddy, Simon Mahler, Alon Goldring, Dr. Vishwa Pal, Asher A. Friesem, and Nir Davidson
    Optics Express 30, 1114-1129 (2022)

    2. Effect of linewidth enhancement factor on the generation of optical vortices in a class-A degenerate cavity semiconductor laser
    Yann Bouchereau, Sopfy Karuseichyk, Raphael Guitter, Dr. Vishwa Pal, Fabien Bretenaker
    Optics Express 30, 15648-15658 (2022)

    3. Generating high-energy densities by side lobe suppression in the far-field of phase locked lasers
    Vasu Dev, Andra Naresh K Reddy, Dr. Vishwa Pal
    Journal of Optical Society of America B 39, 2254-2263 (2022)

    4. Generating asymmetric aberration laser beams with controlled intensity distribution
    Sachleen Singh, Vasu Dev, Dr. Vishwa Pal
    Journal of Optics 24, 125601 (2022)
    1. High-resolution digital spatial control of a highly multimode laser
    C. Tradonsky, S. Mahler, G. Cai, Dr. Vishwa Pal, R. Chriki, A. A. Friesem, and N. Davidson
    Optica 8, 880-884 (2021)

    2. Design of diffractive optical elements for shaping the laser intensity distribution
    Vasu Dev, Andra Naresh Kumar Reddy, Dr. Vishwa Pal
    Springer Proceedings in Physics 258, 89-91 (2021)

    3. Autofocusing and Self-Healing Properties of Aberration Laser Beams in a Turbulent Media
    Vasu Dev, Andra Naresh K. Reddy, Andrey V. Ustinov, Svetlana N. Khonina, Dr. Vishwa Pal
    Physical Review Applied 16, 014061 (2021)

    4. Divergence and self-healing of a discrete vortex formed by phase-locked lasers
    Vasu Dev, Dr. Vishwa Pal
    Journal of Optical Society of America B 38, 3683-3696 (2021)

    5. High-resolution digitally controlled multimode laser
    Chene Tradonsky, Simon Mahler, Dr. Vishwa Pal, Asher A. Friesem, and Nir Davidson
    Optics & Photonics News 32, 34 (2021)
    1. Rapid fair sampling of the XY Hamiltonian with a laser simulator
    Dr. Vishwa Pal, Simon Mahler, Chene Tradonsky, Asher A. Friesem, and Nir Davidson
    Physical Review Research 2, 033008 (2020)

    2. Generation of uniform-intensity light beams with controllable spatial shapes
    Vasu Dev, Andra Naresh Kumar Reddy, Dr. Vishwa Pal
    Optics Communications 475, 126226 (2020)

    3. Generating auto-focused aberration laser beams with different spectral performance
    A. N. K. Reddy, S. N. Khonina, and , Dr. Vishwa Pal
    Journal of Optics  22, 045606 (2020)

    2. Rapid laser solver for the phase retrieval problem
    Chene Tradonsky, Igor Gershenzon, Dr. Vishwa Pal, Ronen Chriki, Asher A. Friesem, Oren Raz, and Nir Davidson
    Science Advances 5, eaax4530 (2019)

    3. Dynamics of dissipative topological defects in coupled phase oscillators
    Simon Mahler, Dr. Vishwa Pal, Chene Tradonsky, Ronen Chriki, Asher A. Friesem, and Nir Davidson
    Journal of Physics B: At. Mol. Opt. Phys. 52, 205401 (2019)

    4. Flat-top laser beams over an extended range
    A. N. K. Reddy, Dr. Vishwa Pal, S. Mahler, A. A. Friesem, and N. Davidson
    Journal of Physics: Conference Series 1410, 012126 (2019)
    1. Generating flat-top beams with extended depth of focus
    Dr. Vishwa Pal, C. Tradonsky, R. Chriki, N. Kaplan, A. Brodsky, M. Attia, , Nir Davidson, and A. A. Friesem
    Applied Optics 57, 4583 (2018)

    2. Spatio-Temporal Supermodes: Rapid reduction of spatial coherence in highly multimode lasers
    R. Chriki, S. Mahler, C. Tradonsky, Dr. Vishwa Pal, A. A. Friesem, and N. Davidson
    Physical Review A 98, 023812 (2018)

    3. Rapid and efficient formation of propagation invariant shaped laser beams
    R. Chriki, G. Barach, C. Tradonsky, S. Smartsev, Dr. Vishwa Pal, A. A. Friesem, and N. Davidson
    Optics Express 26, 4431 (2018)
    1. Observing dissipative topological defects with coupled lasers
    Dr. Vishwa Pal, C. Tradonsky, R. Chriki, , A. A. Friesem, and N. Davidson
    Physical Review Letters 119, 013902 (2017)

    2. Talbot diffraction and Fourier filtering for phase locking an array of lasers
    C. Tradonsky, Dr. Vishwa Pal, R. Chriki, , A. A. Friesem, and N. Davidson
    Applied Optics 56, A126
    1. Controlling spatial coherence
    R. Chriki, Dr. Vishwa Pal, C. Tradonsky, G. Barach, A. A. Friesem, N. Davidson, S. Knitter, C. Liu, B. Redding, M. K. Khokha, M. A. Choma, , and H. Cao
    Optics & Photonics News  27 (12), 35 (2016)
    1. Phase locking of even and odd number of lasers on a ring geometry: effects of topological charge
    Dr. Vishwa Pal, C. Tradonsky, R. Chirki, G. Barach, , A. A. Friesem and N. Davidson
    Optics Express 23, 13041 (2015)

    2. Manipulating the spatial coherence of a laser source
    R. Chriki, M. Nixon, Dr. Vishwa Pal, C. Tradonsky, G. Barach, , A. A. Friesem and N. Davidson
    Optics Express 23, 12989 (2015)

    3. Conversion of out-of-phase to in-phase order in coupled laser arrays with second harmonics
    C. Tradonsky, M. Nixon, E. Ronen, Dr. Vishwa Pal, R. Chirki, , A. A. Friesem and N. Davidson
    Photonics Research 3, 77 (2015)

    4. Optical processing in the aid of phase locking laser arrays
    C. Tradonsky, Dr. Vishwa Pal, R. Chriki, G. Barach, , N. Davidson, and A. A. Friesem
    Asian Journal of Physics 24, 1627 (2015) [Invited article]
    1. Semiconductor laser dynamics with two filtered optical feedbacks
    Dr. Vishwa Pal,  J. S. Suelezer, A. Prasad, , G. Vemuri and R. Ghosh
    IEEE Journal of Quantum Electronics 49, 340 (2013)

    2. Intensity noise correlations in a two-frequency VECSEL
    S. De, Dr. Vishwa Pal, A. El Amili, G. Pillet, G. Baili, M. Alouini, I. Sagnes, , R. Ghosh and F. Bretenaker
    Optics Express 21, 2538 (2013)
    1. Optical phase dynamics in mutually coupled diode laser systems exhibiting power synchronization
    Dr. Vishwa Pal, A. Prasad, , and R. Ghosh
    Journal of Physics B: At. Mol. Opt. Phys. 44, 235403 (2011)

    2. Observation of noise phase locking in a single-frequency VECSEL
    A. El Amili, Dr. Vishwa Pal, F. Goldfarb, R. Ghosh, M. Alouini, ,  I. Sagnes and F. Bretenaker
    Optics Express 19, 17250 (2011)
    1. Measurement of the coupling constant in a two-frequency VECSEL
    Dr. Vishwa Pal, P. Trofimoff, B.-X. Miranda, G. Baili, M. Alouini, L. Morvan, D. Dolfi, F. Goldfarb, I. Sagnes, , R. Ghosh and F. Bretenaker
    Optics Express 18, 5008 (2010)

    Open Position


    • PhD positions are available. Highly motivated candidates having interest in the field of Laser Physics, Optics & Photonics are encouraged to apply. Interested candidates can contact on vishwa.pal@iitrpr.ac.in.
    • Postdoc positions: Candidates with background in the field of Laser Physics, Optics & Photonics can send your CV on vishwa.pal@iitrpr.ac.in

    Teaching

    Undergraduate:

    • Optics & Photonics (PH303)
    • Engineering Photonics (PH457)
    • Technology Museum Lab (GE101)
    • Physics Lab (PH102)

    Postgraduate & PhD:

    • Modern Optics (PH511)
    • Nonlinear Optics (PH510)
    • Experimental Methods (PH422)
    • Laser Physics (PH614)
    • Physics of EM Waves (PH603)
    • Physics Lab II (PH510)