Physics Society of J. B. College (PSJBC) organized the 4^th talk of the Distinguished Lecture Series on 12^th September, 2018 at 11 am in the Conference Hall1 of J. B. College. The talk was delivered by Prof. Gaurangadhar Baruah, Former Professor, Head and UGC Emeritus Professor, Department of Physics, Dibrugarh University, Dibrugarh, Assam. Prof. Baruah is one of the best scientists in the field of molecular Spectroscopy, Semi-classical and Quantum Theory of Lasers, X-ray Laser and Quantum Optics. Notably Prof. Baruah pursued his research work in Banaras Hindu University with the advice of Sir C V Raman. He was also the sectional President of Physics at the 85^th  sessions of Indian Science Congress at Hyderabad and Recorder of Physics Section of Indian Science Congress Association during 1995-96.