**Acknowledgements**

The authors acknowledge the financial support provided by BNDES (09.2.1458.1), FINEP (01.14.0242.00), MMOptics industry (São Carlos, SP, Brazil), São Paulo Research Foundation - FAPESP (2013/07276-1), CEPOF (2009/54035-4 – EMU) and INCT (2014/50857-8).

They are also indebted to the Technological Support Laboratory (São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil) for technological support.
