Tuning plasmon resonance in depth-variant plasmonic nanostructures

Highlights: • We show plasmonic nanostructures for tunable plasmon resonances in optically thick metal films. • Precise domination on etching depth is realized via cross-section investigation using scanning electron microscopy. • The approach developed in this work is useful for optical devices design and development in imaging and display applications. We demonstrate coaxial-aperture-based plasmonic nanostructures for tunable plasmon resonances in optically thick metal films. Accurate control of etching depth is achieved via cross-section investigation under a scanning electron microscope. Colorful surfaces are observed with varying geometries. The approach developed in this work is potentially useful for optical devices design and development in nanophotonics and integrated optics, especially for imaging and display applications.