1. Department of Physics, Instituto Tecnológico de Aeronáutica, DCTA, 12228-900 São José dos Campos, Brazil
2. Department and Centre of Physics, and QuantaLab, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
3. International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga, 4715-330 Braga, Portugal