After postdoctoral work at the University of Oxford and the Tata Institute of Fundamental Research, Mumbai he joined the Rajabazar Science College campus of University of Calcutta in 1980 as a lecturer in physics, where he became Reader and then the Sir Tarak Nath Palit Professor. During his tenure at the University of Calcutta, he was a Scientific Associate (1983–84) at CERN, Senior Indo-US Fulbright Fellow (1988–89) at the Lawrence Berkeley Laboratory and Senior Marie Curie Fellow (1994) at the University of Cambridge. He was also a Visiting Professor (1998) at the Oklahoma State University. He was the Director of the Harish-Chandra Research Institute, Allahabad from 2005 to 2011 after which he rejoined the University of Calcutta as faculty.