Quantum well effect based on hybridization bandgap in deep subwavelength coupled meta-atoms

In this paper, quantum well (QW) effect in a hybridization bandgap (HBG) structure via hiring deep subwavelength coupled meta-atoms is investigated. Subwavelength zero-index-metamaterial-based resonators acting as meta-atoms are side-coupled to a microstrip, forming the HBG structure. Both numerical and microwave experimental results confirm that, through properly hiring another set of meta-atoms, band mismatch between two HBGs can be introduced resulting in the HBG QW effect. Compared with the conventional QW structure based on Bragg interferences in photonic crystal, the device length of the proposed HBG QW structure can be reduced to only 1/4, demonstrating well the deep subwavelength property. Therefore, the above features make our design of HBG QW structures suitable to be utilized as multi-channel filters or multiplexers in microwave and optical communication system.