A tunable perfect meta‐absorber (PMA) composed of an electric split‐ring resonator (eSRR) and a cross‐shaped nanostructure is proposed. Owing to the electromagnetic coupling effect generated between dipole and inductive–capacitive (LC) resonances, the PMA exhibits perfect absorption, tunable resonance, variable optical attenuation, and switchable polarization‐dependence/independence characteristics. Furthermore, the PMA is demonstrated to be feasible for sensing applications. The PMA exhibits high sensing performance with a sensitivity of 1200 nm/RIU. Such results indicate that the proposed PMA can be used in variable optical attenuators, polarization switches, tunable absorbers, and sensors applications.

No abstract

No abstract

In this Letter, by cascading several bichromatic photonic crystals we demonstrate that the quality factor can be much larger compared with that in an isolated cavity without increasing the total size of a device. We take a lithium niobate photonic crystal as an example to illustrate that the simulated quality factor of the cascaded cavity can reach 105 with a 70° slant angle, which is an order of magnitude larger than that in an isolated cavity. The device can be fabricated easily by current etching techniques for lithium niobate. We have fabricated the proposed device experimentally including holes with ∼70° slant angle. This work is expected to provide guidance to the design of photonic crystal cavities with high quality factor.

No abstract