Agradecimentos: D.S.F. thanks the financial support from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq (150232/2012-8), Brazil. We thank FAPESP and CNPq for financial support through the National Institute for Science and Technology of Quantum Information (INCT-IQ) and the Optics and Photonics Research Center (CePOF)