Linear and Nonlinear Optical Field Manipulations with Multifunctional Chiral Coding Metasurfaces

Abstract

the chiral light-matter interactions include two distinct phenomena: circular dichroism characterized by the absorption difference between transmitted left circularly polarized (LCP) and right circularly polarized (RCP) lights [4] and circular birefringence caused by phase accumulation difference between LCP and RCP lights. [5] Recently, chirality induced by artificial nanostructures and their 3D arraysmetamaterials has drawn much attention in the scientific community due to the arbitrary symmetric design and abundant optical resonance engineering of nanostructures. Such effects enable significant polarizability tensor manipulation of the optical fields with high degree of freedom (DOF). [6] Based on different local chiral electromagnetic resonances of the nanostructures, researchers have developed numerous functional chiral designs such as chiral biosensing, [7] chiral bound states in the continuum, [8] Janus plasmonic helical nanoapertures, [9] and weak chirality for strong coupling between resonant states. [10] In the past decade, metasurfaces as planar counterparts of metamaterials have been extensively investigated due to their exotic electromagnetic properties for efficient scattering control of the electromagnetic waves. [11][12][13][14][15] In contrast to conventional optics, metasurfaces consist of arrays of subwavelength elements ("meta-atoms") that can locally manipulate light−matter interactions. Spatially varying meta-atoms allow the control of the polarization, phase, and amplitude of light, leading to high DOF to manipulate the electromagnetic waves from near-fields to far-fields. [16,17] The light−matter interactions supported by the meta-atoms include local multi-polar resonances [18,19] and near-field coupling resonances such as Fano resonances [20] and bound states in the continuum. [21,22] Generally, such resonances are accompanied by enhancement of local electric or magnetic fields, leading to enhanced nonlinear responses such as second harmonic generation (SHG) and third harmonic generation (THG). [23][24][25] Although the overall nonlinear efficiency of the reported metasurfaces is still not comparable to that in conventional nonlinear crystals, the nonlinear efficiency of metasurfaces is much higher when considering their planar nature. Most importantly, metasurfaces provide an efficient platform for optical frequency mixing and high harmonic generation. [26][27][28] On the other hand, based on a variety of local resonances of meta-atoms, metasurfaces can be designed to carry different Optical chirality, which describes the property of asymmetric light-matter interactions for different handedness of polarization, plays an important role in physical photonics, biochemical processes, and molecular recognition. Recently, asymmetric optical responses of chiral nanostructures provide a wide platform for arbitrary and artificial manipulation of optical chirality. Here, a design strategy is theoretically and experimentally introduced to realize a spin-selective coding metasurface in both linear a...

High-Q and Intense Lattice Plasmon Resonance in Hexagonal Nonclose Packed Thin Silver Nanoshells Array

“…Localized surface plasmons (LSPs) refer to the collective oscillation phenomenon of free electrons in the conduction band of metallic nanoparticles excited by electromagnetic waves . The abilities of LSP to surpass the diffraction limit of conventional optics and enhance the light-matter interactions have attracted significant attentions. , These unique properties enable the transformation and manipulation of photonics, electronics, and nanotechnology, including biosensing, nonlinear optics, nanolasers, strong local field enhancement, and metamaterials. − However, the presence of huge nonradiative and radiative loss of metallic nanostructures results in a low quality factor ( Q ∼ 10 1 ) for LSPs. , Consequently, the performance of many applications of plasmonic-based nanodevices is limited . Current research focuses on addressing this issue by exploring various mechanisms to achieve high- Q plasmonic resonance, such as utilizing alternative plasmonic materials, reducing surface roughness, , incorporating gain media, , utilizing plasmonic Fano resonances , and employing lattice plasmon resonance (LPR). − …”

Multichannel Linear and Nonlinear Information Encryptions with Malus Metasurfaces

“…The phase-matching condition of the nonlinear process is released in metasurfaces because of their nanoscale dimension. Furthermore, numerous nonlinear wavefront manipulations have been achieved, such as nonlinear holograms, [35,36,38,51] nonlinear optical vortexes, [5,52] and nonlinear metalenses. [53,54] Benefiting from the simple relationship between the phase and the rotation angle of structures, the nonlinear Pancharatnam-Berry (PB) phase has been extensively employed in engineering the wavefront of nonlinear signals.…”

“…[35,37] Nonlinear multichannel optical information multiplexing has also been successfully implemented in previous publications. [52,55] Moreover, optical information can be constructed in both linear and nonlinear regimes simultaneously, providing new possibilities for information encryption. [5] By expanding the PB phase and Malus's law to nonlinear optical regimes, different optical information can be encrypted into different frequency or polarization channels.…”

Multi-Objective Optimization of Chiral Metasurface for Sensing Based on a Distributed Algorithm

“…chiral metasurfaces. Chiral metasurfaces have significant importance in various optical applications, including molecular recognition [1], biosensing [2], and optical information processing [3]. Additionally, chiral metasurfaces offer several advantages for refractive index sensing applications, such as high sensitivity, a broad operation wavelength range, fast response, and high selectivity [4], [5].…”