An azimuthally polarizing photonic crystal fibre with a central gold nanowire

An air–silica photonic crystal fibre with a gold nanowire at core centre is shown to support a low-loss azimuthally polarized mode. Since all the other modes have very high attenuation, the fibre effectively supports only this mode, acting as a single-polarization fibre with an extinction ratio >20 dB cm−1 over a broad range of wavelengths (550–1650 nm in the device reported). It can be used as an effective azimuthal mode filter.