Numerical study of the plasmonic slab lens for improving direct-write nano lithography.

Plasmonic direct-write lithography (PDWL) provides a potential tool for the fabrication and manufacturing at the nano scale due to its high-resolution and low-cost. However, the shallow exposure depth hinders its practical application. Here, we incorporate the plasmonic slab lenses (PSLs) into PDWL to amplify and compensate evanescent waves, leading to improved light intensity, depth, resolution and better tolerance to the air gap beyond the near field optical lithography.

Forty-Nanometer Plasmonic Lithography Resolution with Two-Stage Bowtie Lens.

Optical imaging and photolithography hold the promise of extensive applications in the branch of nano-electronics, metrology, and the intricate domain of single-molecule biology. Nonetheless, the phenomenon of light diffraction imposes a foundational constraint upon optical resolution, thus presenting a significant barrier to the downscaling aspirations of nanoscale fabrication. The strategic utilization of surface plasmons has emerged as an avenue to overcome this diffraction-limit problem, leveraging their inherent wavelengths.

Pure toroidal dipole in a single dielectric disk.

The toroidal dipole is a peculiar electromagnetic excitation and has attracted increasing interests because of unusual radiation characteristics. However, the realization of toroidal moment requires complicated structure and are often disturbed by the conventional electric and magnetic multipoles. In this paper, we explore the electromagnetic properties of a simple dielectric disk illuminated by a focused radially polarized beam and demonstrate a pure toroidal dipolar response.

Tunable anisotropic parameters realized by metal-dielectric hybrid meta-atoms.

Rational design of the structure enables metamaterials to go beyond the ingredients and achieve unprecedented material properties. However, the realization of complicated and anisotropic electromagnetic parameters relies on the elaborate design of building blocks, and the mutual coupling between the anisotropic responses makes precise control of material parameters even more difficult. Here, we propose a metal-dielectric hybrid metamaterial, not only realizing the decoupling between anisotropic electromagnetic responses, but also establishing a one-to-one correspondence between independent geometric dimensions and anisotropic parameter components.

Energy Band Attraction Effect in Non-Hermitian Systems.

The energy band attraction (EBA) caused by the nonorthogonal eigenvectors is a unique phenomenon in the non-Hermitian (NH) system. However, restricted by the required tight-binding approximation and meticulously engineered complex potentials, such an effect has never been experimentally demonstrated before. Here by a suitable design of all-dielectric Mie resonators in a parallel-plate transmission line, we for the first time verify the photonic analog of the EBA effects both theoretically and experimentally.