Tunable plasmofluidic lens for subwavelength imaging

A tunable plasmofluidic lens consisting of nanoslit arrays on a metal film is proposed for subwavelength imaging in far field at different wavelengths. The nanoslit arrays with constant depths but varying widths could generate desired optical phase retardations based on the propagation property of the surface plasmon polaritons (SPPs) through the metal-dielectric-metal (MDM) nanoslit waveguide. We demonstrate the tunability of the plasmofluidic lens for subwavelength imaging by changing the surrounding dielectric fluid. This work provides a novel approach for developing integrative tunable plasmofluidic lens for a variety of lab-on-chip applications.