1. Department of Physics, Indira Institute of Engineering & Technology, V.G.R. Nagar, Pandur, Thiruvallur District, 631 203, India
2. Department of Physics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai 602 105, India
3. Department of Electronics and Communication Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Thandalam, Chennai, 602 105, India