Surface plasmon photonic bandgap in azopolymer gratings sputtered with gold

Surface plasmons (SPs) are generated on a doubly corrugated gold-covered surface. The corrugations were obtained by direct holographic inscription of surface relief gratings on an azopolymer film. This method permits the superposition of multiple surface profiles with easy control of the grating spacing. One grating is inscribed to act as coupler for the incident light to the SP and a second grating is inscribed to generate a gap in the SP dispersion curve. The coupling and the gap can be observed by measuring the reflectivity of the gold surface as a function of the angle of incidence and the wavelength of the probe beam.