Efficient light redirection via stretched field resonance in dielectric meta-resonator.

Light redirection plays an important role in photonic integrated circuit system, which attracts much attention on account of thriving application prospects from microwave to visible frequency. By treating a two-dimensional photonic crystal array as a dielectric resonator with low effective index n << 1, a new strategy of one-direction semi-enclosed meta-resonator is proposed for light redirection and splitting with a high efficiency beyond 90%. Instead of zero-index material, the phenomenon of significant collimating radiations with zero phase delay can also be achieved through a meta-resonator of low effective index to stretch the internal resonant field with a wavelength much longer than that in air. The geometrical dimensions and structural parameters of the meta-resonator offer a great design flexibility for modulating the operating frequency. The numerical simulation and experimental results perfectly coincide with the theoretical predictions. This strategy can also be extended to other artificial metamaterials and three-dimensional cases, which may offer fantastic possibilities to the development of integrated photonics.