Dear Mehdi,

This article on visible light response should make for a good starting point: Ruoff, Rodney S. et al "Simple Approach for High-Contrast Optical Imaging and Characterization of Graphene-Based Sheets." Nano Letters (2007), 7(12), 3569-3575

You can download the PDF directly from:

http://bucky-central.me.utexas.edu/RuoffsPDFs/168.pdf

I suggest looking at articles citing this one for information on microwave properties specifically.

Dear Toma 

thank you very much, i will read it