Light Redirection and Splitting via Meta-resonator Based on Photonic Crystal with Low Effective Index

Dielectric resonator antennas are usually utilized to radiate communication signal into air at microwave domains. In this paper, we bring the concept of rectangular dielectric resonator into photonic crystal array to propose a novel scheme of one-direction semi-enclosed meta-resonator for light redirection and splitting. According to the principle of scale invariance of photonic crystal, this scheme can be achieved from microwave to optical regimes. By exploiting the intimate relationship between electric-field oscillation and resonator characteristics, we investigate the radiation properties of this meta-resonator and find that pure standing wave resonance can be excited along one-direction with stretched wavelength based on the small effective index of n
_eff
≪ 1, simultaneously, energy of electric-field oscillation fixed in incident direction can be radiated into air with a high efficiency and perfect self-collimation. Zero phase delay can be achieved at the fundamental resonance mode, instead of zero-index material. For the high-order resonant modes, symmetric multibeam-splitting with constant 0 or π phase shift can be realized. Numerical simulations and experiments significantly coincide with the theoretical predictions. We believe that this strategy may offer fantastic possibilities to the development of integrated photonics.