Efficient waveguiding inside low refractive index media is of
key importance for a great variety of applications that demand
strong light–matter interaction on small geometric footprints.
Here, we demonstrate efficient light guidance in single-defect
dual-ring light cages over millimeter distances that are integrated on silicon chips via direct laser writing. The cages consist of two rings of high aspect-ratio polymer strands (length
5 mm, aspect ratio >1000) hexagonally arranged around a
hollow core. Clear-core mode formation via the photonic band
gap effect is observed, with the experiments showing pronounced transmission bands with fringe and polarization
contrasts of >20 dB and >15 dB, respectively. Numerical
simulations confirm our experiments and reveal the dual-ring
arrangement to be the optimal geometry within the light cage
concept. Particularly, the side-wise access to the core regions
and the chip integration makes the light cage concept attractive for a great number of fields such as bioanalytics or
quantum technolog