Propagation of surface polaritons over macroscopic distances at optical frequencies

We report the propagation of surface polaritons over macroscopic distances along copper-air interfaces at 10.6 μm wavelength using a prism coupling technique for generating and detecting the surface modes. The measured propagation length (～ 1.6cm) is in agreement with theoretical estimates based on available optical data. The surface polaritons are easily observed visually using Radelin thermographic phosphor paper.