Dynamic Tuning of Gap Plasmon Resonances Using a Solid-State Electrochromic Device.

Area of Science:

• Nanophotonics
• Materials Science
• Electrochemistry

Background:

• Plasmonic antennas and metasurfaces offer precise light control but typically have fixed optical properties post-fabrication.
• Dynamic tuning of optical properties, especially in the visible spectrum, is crucial for advanced optics applications.

Purpose of the Study:

• To demonstrate dynamic tuning of polarization-dependent gap plasmon resonators using electrochromic materials.
• To achieve active, low-power, and nonvolatile control over optical properties in the visible range.

Main Methods:

• Incorporation of electrochromic tungsten oxide (WO3) into gap plasmon resonators.
• Electrochemical tuning of WO3's refractive index via lithium insertion/removal in a solid-state device.
• Characterization of resonant wavelength shifts under applied electrochemical bias.

Main Results:

• Continuous and reversible tuning of resonant wavelength by up to 58 nm.
• Achieved tuning with less than 2 V electrochemical bias.
• Demonstrated nonvolatile tuning, with the resonator maintaining its state for tens of minutes under open circuit conditions.

Conclusions:

• Electrochromic WO3 enables dynamic and reversible tuning of gap plasmon resonators in the visible spectrum.
• The developed solid-state devices offer a promising platform for tunable structural color and active optical components.
• Low-voltage operation and nonvolatile memory characteristics open avenues for energy-efficient optical applications.