1. Department of Physics, Jawaharlal Nehru Technological University Ananthapur (JNTUA), Anantapur, India
2. Solar Energy Laboratory, Sree Vidyanikethan Engineering College, Tirupati, India
3. Center for Applied Sciences, Sree Vidyanikethan Engineering College, Tirupati, India
4. Department of Physics, Government Degree College, Pakala, India