Self-assembled hollow waveguides with hybrid metal-dielectric Bragg claddings.

We report on the fabrication and characterization of integrated hollow waveguides cladded by gold-terminated, omnidirectional Bragg reflectors. The hollow waveguide channels were realized by the controlled formation of straight-sided delamination buckles within a multilayer thin film stack. An optimized process produced low-defect, straight-sided buckles with base widths from 10 to 80 mum, and corresponding peak core heights from ~0.7 to ~4 mum, on a single sample. The waveguides described have upper and lower cladding mirrors of 4 and 5.5 periods, respectively. Gold termination of the cladding reflectors significantly reduces the propagation loss of air-guided modes. The minimum propagation loss is less than 4 dB/cm in the near infrared, corresponding to upper and lower cladding reflectance of ~ 0.999. The main details of the guiding mechanism are well approximated by a simple ray-optics model.