Beam Collimation Using an Anisotropic Metamaterial Slab Without Any Nanometer-Sized Aperture

Abstract

Plasmonic beam collimation effect has been thoroughly investigated based on the well-known nanometerscale bull's eye structure formed by complex and high-cost fabrication processes. In this work, we report our effort for attaining beam collimation using an anisotropic metamaterial (AMM) slab that consists of a stack of alternating metal/dielectric layers and an integrated top metal grating. The results show that AMM slab allows creating the beam collimation effect similar to that of the bull's eye structure, an enabling technology for practical application due to its simple architecture and cost benefits. The excitation of surface plasmons at the AMM/air interface is derived. The structure of the AMM slab and its impact on beaming performance were analyzed using the effective medium theory and Finite Element Method.

Magnetic hydrogels with ordered structure for biomedical applications

“…Many researches have proved that the drug release from hydrogels could be controlled by magnetic field ( Zhang et al, 2016a ; Li et al, 2021 ). The magnetic nanoparticles tend to move in the polymer network and change the porosity under the external magnetic stimulation, thus achieving the control of drug release ( Lin and Metters, 2006 ).…”

“…The resulting heat can speed up the molecular motion that promote the diffusion and release of drug. The degradation of polymer matrix can also been tuned by magneto-thermal effect, leading the drug release ( Li and Mooney, 2016 ; Zhang et al, 2016a ). For example, Hu et al (2015a) used magnetic field to control drug release from magnetic hydrogels with anisotropic structure.…”

“…Many biological tissues such as eye, muscle, skin and cartilage also present well-defined hierarchical, anisotropic structures ( Zhang et al, 2016a ; Shi et al, 2020b ; Park and Kim, 2020 ; Sun et al, 2020 ). The intrinsic ordered structure of tissues plays an essential role in physiological functions and activities, such as muscle contraction and cell migration ( Grazi, 2008 ; Zhukova et al, 2017 ).…”