Actively tunable plasmonic lens for subwavelength imaging at different wavelengths

TL;DR

This paper introduces a tunable plasmonic lens with nanoslits capable of subwavelength imaging at various wavelengths, adjustable by changing the surrounding dielectric fluid, promising advancements in lab-on-chip technologies.

Contribution

It presents a novel, in-plane tunable plasmonic lens design using nanoslits with variable widths for adjustable subwavelength imaging.

Findings

Achieved tunable subwavelength imaging with FWHM of 0.37-0.47.

Demonstrated tunability by adjusting the surrounding dielectric fluid.

Provided a new approach for lab-on-chip applications.

Abstract

A type of tunable plasmonic lens with nanoslits is proposed for subwavelength imaging in the far field at different wavelengths. The nanoslits array in the plasmonic lens, which have constant depths but varying widths, could generate desired optical phase retardations based on the particular propagation property of the Surface Plasmon Polaritons (SPPs) in the metal-dielectric-metal (MDM) slit waveguides. We theoretically and numerically demonstrate the tunability of a single plasmonic lens for subwavelength imaging (full width at half maximum, 0.37 ~0.47) by adjusting the surrounding dielectric fluid, thereby realizing the compact in-plane tunable plasmonic lens. This work provides a novel approach for developing integrative tunable plasmonic lens for a variety of lab-on-chip applications.