Multipole analysis of photonic crystal fibers with coated inclusions.

Photonic crystal fibers (PCF) containing coated holes have recently been demonstrated experimentally, but haven't been studied theoretically and numerically thus far. We extend the multipole formalism to take into account coated cylinders, and demonstrate its accuracy even with metallic coatings. We provide numerical tables for calibration of other numerical methods. Further, we study the guidance properties of several PCF with coated holes: we demonstrate that the confinement mechanisms of PCFs with high index coated holes depend on wavelength, and exhibit plasmonic resonances in metal coated PCFs.