[1] St Martins Engineerirng Coll, Dept Freshmen Engn Phys, Secunderabad 500100, Telangana, India
[2] CMR Engn Coll, Dept Phys, Hyderabad 501401, Telangana, India
[3] Sastra Univ, Thanjavur, Tamilnadu, India
[4] GDC Chevella, Chevella, Telangana, India