Linear and Nonlinear Optical Field Manipulations with Multifunctional Chiral Coding Metasurfaces

摘要

Optical chirality, which describes the property of asymmetric light–matterinteractions for different handedness of polarization, plays an important rolein physical photonics, biochemical processes, and molecular recognition.Recently, asymmetric optical responses of chiral nanostructures provide awide platform for arbitrary and artificial manipulation of optical chirality.Here, a design strategy is theoretically and experimentally introduced torealize a spin-selective coding metasurface in both linear and third harmonicregimes with giant chirality. Significant chiral transmission and wavefrontcontrol are realized by a chiral coding metasurface composed of amorphoussilicon (a-Si) resonators with C_2 symmetry. The resonators and the enantiomersare encoded with different transmission amplitude and phase. Theinformation channels are expanded to six-fold with simultaneous multi-focifocusing and multi-vortex generation operating in different polarization andlinear/nonlinear channels. The nonlinear chiral high-contrast imaging isalso achieved for spin-selective pattern information transmission. The studysignificantly expands the information capacity of coding metasurfaces, andcan be readily applied in optical systems for information transmission in bothlinear and nonlinear regimes.