Tunable Reflection-Based Nanoimaging Using Electrical Control of Hyperbolic Polaritons

Abstract

We report on the design of a tunable reflection-based lenslet composed of a periodic metal-dielectric multilayer system of silver and 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) that is capable of resolving fine object details with subwavelength resolution of up to λ/9 in the near field. Total internal reflection is achieved on the lenslet edges, with electrical control of the hyperbolic polaritons allowing tunability over a wide spatial and spectral range. Here, we demonstrated imaging performed successfully with and without electrical biasing for three different wavelengths, of 603 nm, 659 nm, and 715 nm. We also demonstrated how the effective medium description may moderately overestimate near-field nanoimaging when accounting for the individual elements of the lenslet. Remarkably, this study introduces novel pathways to practically realize dynamically tunable broadband subdiffraction spectroscopic imaging or near-field lithography.