(a) Illustration of a β-phase vertical cylinder of diameter φ embedded within a thin film of glassy-phase PFO. (b) Full-field dispersion of the supported optical modes propagating along the cylinder axis. The inset shows the intensity distribution (darker=higher) of the HE11 mode for φ=400 nm; the dashed circle delineates the cylinder cross-section and confirms the high degree of confinement. (c) Calculated far-field radiation profiles of HE11 (red) and HE21 (blue) guided modes emanating from the cylinder cross-sections at the thin film surface. Two cylinder diameters (φ=400 and 800 nm) are shown.