  In developing strategies of manipulating surface electromagnetic waves, it
has been recently recognized that a complete forbidden band gap can exist in a
periodic surface-wave photonic crystal, which has subsequently produced various
surface-wave photonic devices. However, it is not obvious whether such a
concept can be extended to a non-periodic surface-wave system that lacks
translational symmetry. Here we experimentally demonstrate that a surface-wave
photonic quasicrystal that lacks periodicity can also exhibit a forbidden band
gap for surface electromagnetic waves. The lower cutoff of this forbidden band
gap is mainly determined by the maximum separation between nearest neighboring
pillars. Point defects within this band gap show distinct properties compared
to a periodic photonic crystal for the absence of translational symmetry. A
line-defect waveguide, which is crafted out of this surface-wave photonic
quasicrystal by shortening a random row of metallic rods, is also demonstrated
to guide and bend surface waves around sharp corners along an irregular
waveguiding path.
