Department of Physics, Indian Institute of Technology Bombay, Mumbai, India

ToPP Group

Topological Photonics and Polaritonics Group


Welcome to the ToPP Research Group!

We are a dynamic group of researchers based at IIT Bombay, working on exciting theoretical problems in photonics, condensed matter physics, topological physics, light–matter interactions, and related areas. Our research focuses on uncovering novel physical phenomena in topological photonics, exciton-polaritons, and topological lasers, and on understanding how topology, quantum effects, and nonlinear interactions can be harnessed to create new regimes of light–matter physics. We aim to design systems that realize robust and functional photonic technologies, with potential applications in topological lasers, polariton transistors, logic gates, quantum emitters, and other next-generation photonic devices. We are also actively incorporating machine learning and data-driven computational approaches to accelerate the discovery, optimization, and inverse design of photonic and polariton platforms.



Recent News


  • September 2026: Three of our PhD students, Abhijit, Prem, and Neha, have suessfully defended their first Annual Progress Seminar. Congratulations to all!
  • August 2026: Dr. Deep’s collaborative work on higher-order antichiral hinge states in a three-dimensional gyromagnetic photonic crystal has now been published in Nature Communications.

    Dr. Deep has also presented his Annual Research Progress Seminar and successfully passed. Heartiest congratulations to him on these double achievements!

    We warmly welcome Mr. Jahidul Islam and Mr. Saurav Prasad as M.Sc. Project Students.

  • June 2026: Dr. Dheerendra presented his Annual Research Progress Seminar and successfully passed.
  • May 2026: Our intern, Ghanshyam, presented his work at the IIT Bombay Research Internship Poster Presentation on 22nd May.
  • February 2026: Our Ph.D. student, Mousam, has successfully defended his first APS seminar. Congratulations to him on this achievement!
  • January 2026: We warmly welcome Mr. Abhijit Das as our new Ph.D. student, Mr. Ghanshyam Purohit as an intern under the IIT Bombay Internship Program, and Mr. Sandipan Biswas as an M.Sc. project student.
  • December 2025: Members of the ToPP Group, along with other members of the Photonics Student Chapter, actively participated in TechConnect 2025. To learn more about the activities of the Photonics Student Chapter, please visit the Student Chapter Website.
  • November 2025: Prof. Subhaskar delivered an invited talk on “Axion Photonic Crystal” at the OPTIQ Conference in Kochi, Kerala, India [Conference Link].
  • October 2025: Prof. Subhaskar has joined the Editorial Board of Scientific Reports and is a Guest Editor for the Special Issue on Polaritons [Link].
  • September 2025: We welcome Dr. Deep Mondal, who has joined us as an Institute Postdoctoral Fellow.
  • August 2025: We are delighted to host Prof. Daniel Leykam from the Singapore University of Technology and Design (SUTD) during his visit to IIT Bombay.
  • August 2025: Our group has organized a Workshop on Recent Trends in Optics and Photonics, sponsored by the SCPP project at IIT Bombay [Workshop Link].
  • August 2025: A warm welcome to our PhD students — Mr. Mousam Dey, Ms. Neha Bhoria, and Mr. Prem Kumar Mourya.
  • July 2025: We are pleased to welcome our first group member, Dr. Dheerendra Singh, who joins us as an Institute Postdoctoral Fellow.