Grating-coupled surface plasmons at microwave frequencies

This work presents a detailed investigation of electromagnetic coupling to the surface plasmon-polariton (SPP) at microwave frequencies. We have recor ded the wavelength-dependent reflectivity from a metallic sinusoidal diffra ction grating of pitch 15 mm. In order to minimize the problems associated with nonplanar incident wavefronts, we have developed an apparatus that col limates the incident beam. We illustrate resonant coupling to the SPP at wa velengths of the order of 10 mm. The wavelength-dependent reflectivities re corded have been successfully fitted using a differential formalism of coni cal diffraction with a single set of grating parameters describing the grat ing profile and metal permittivity. (C) 1999 American Institute of Physics. [S0021-8979(99)08215-8].