Dual-Field Superfocusing Based on Near-field Metasurfaces

In this work, a terahertz near-field metasurface is proposed to superfocus both electric and magnetic fields. To achieve a sharp dual-field superfocusing, a sort of minuscule unit cell is designed to elaborately arrange the array accordingly. The full widths at half-maximum (FWHMs) of the electric and magnetic fields are 0.079 lambda and 0.052 lambda at a distance of 0.1 lambda. The proposed dual-field superfocusing holds potential benefits for multiple-target sensing, extreme subwavelength lithography, super-resolution imaging, and data storage and access.