1. Telecommunication Engineering Department Federal University of Ceará (UFC) P.O. Box 6007 Fortaleza Ceará 60755‐640 Brazil
2. Federal Institute of Education Science and Technology of Ceará (IFCE) Campus Maranguape Maranguape Ceará 61940‐750 Brazil
3. Telecommunication and Materials Science and Engineering of Laboratory (LOCEM) Physics Department Federal University of Ceará (UFC) Campus Pici Fortaleza 60040‐531 Ceará Brazil
4. Federal Institute of Education Science and Technology of Ceará (IFCE) PPGET Fortaleza 60040‐531 Ceará Brazil
5. Department of Organic and Inorganic Chemistry Federal University of Ceará (UFC) Fortaleza 60040‐531 Ceará Brazil
6. Federal Institute of Education Science and Technology of Ceará (IFCE) Campus Camocim Camocim Ceará 62400‐000 Brazil
7. Group Functional Nanomaterials Physics Department Federal University of Sergipe Sao Cristóvão SE 49100‐000 Brazil