Observation of resonant states in negative refractive photonic crystals S. Romano, A. C. De Luca, E. De Tommasi, S. Cabrini, I. Rendina and V. Mocella J. Eur. Opt. Soc.-Rapid Publ., 9 (2014) 14006 Published online: 25 January 2014 DOI: 10.2971/jeos.2014.14006