1. Indian School of Mines, Department of Applied Physics, Dhanbad 826004, IndiabPolitecnico di Torino, Department of Electronics and Telecommunications, 24 Corso Duca degli, Abruzzi, Torino 10129, Italy
2. Indian School of Mines, Department of Applied Physics, Dhanbad 826004, India
3. Politecnico di Torino, Department of Electronics and Telecommunications, 24 Corso Duca degli, Abruzzi, Torino 10129, Italy