1. School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
2. Department of Electronics and Telecommunication Engineering, Jadavpur University, Jadavpur, Kolkata 700032, India
3. Department of Physics, Acharya Prafulla Chandra College, New Barrackpore, Kolkata 700131, India
4. Department of Physics, Jadavpur University, Jadavpur, Kolkata 700032, India