Active plasmonic devices with anisotropic optical response: a step toward active polarizer

Area of Science:

• Nanotechnology
• Materials Science
• Optics

Background:

• Metallic nanoparticles (NPs) exhibit localized surface plasmon (LSP) resonances, which are sensitive to their environment.
• Controlling NP optical properties is crucial for developing advanced photonic devices.

Purpose of the Study:

• To demonstrate control over the optical properties of metallic NPs using an electrochemical switch based on conducting polymers (CPs).
• To investigate the wavelength-dependent dielectric function of CPs and its effect on LSP quenching in NPs.

Main Methods:

• Fabrication of an electrochemical switch using a thin layer of conducting polymer (CP) and metallic nanoparticles (NPs).
• Characterization of localized surface plasmon (LSP) resonance quenching in oblate and prolate NPs.
• Analysis of the CP dielectric function's variation with wavelength.

Main Results:

• The quenching of LSP resonance in oblate NPs is frequency-dependent, attributed to wavelength-dependent CP dielectric function.
• Prolate NP arrays exhibit complete LSP quenching along the major axis and modulated damping along the minor axis.
• Anisotropic optical response is achieved by combining electroactive CPs and prolate NPs.

Conclusions:

• Electrochemically controlled conducting polymers offer a method for tuning metallic nanoparticle optical properties.
• The developed system enables the design of active plasmonic devices with switchable anisotropic optical responses.
• These devices show potential applications as active filters and polarizers.