Surface acoustic wave-tuned plasmonic resonances in liquid crystal-covered gold nanostructures

In this work, we propose an acoustically tunable plasmonic device based on liquid crystal (LC)-covered gold nanostructures. By utilizing the standing surface acoustic waves (SSAWs) to realign LC molecules, one can effectively tune the effective refractive index of LCs, and subsequently tune localized surface plasmon resonances (LSPRs) of the gold nanostructures. A 15 nm blue shift of the LSPR peak with the driving voltage of 400 mVpp is experimentally observed. Upon removal of the applied SSAWs, the LC molecules can return to their original orientation, and so does the LSPR peak. Besides the excellent reversibility, this active plasmonic device also features low power consumption and easy integration, which could find many potential applications including switches, modulators, and couplers.

Automated summary

In this work, we propose an acoustically tunable plasmonic device based on liquid crystal (LC)-covered gold nanostructures. The effective refractive index of LCs can be tuned by utilizing standing surface acoustic waves (SSAWs) to realign LC molecules, which subsequently tunes localized surface plasmon resonances (LSPRs) of the gold nanostructures. A 15 nm blue shift of the LSPR peak is observed experimentally with a driving voltage of 400 mVpp. The LC molecules and LSPR peak can return to their original states upon removal of the applied SSAWs. This active plasmonic device features excellent reversibility, low power consumption, and easy integration, making it suitable for various applications including switches, modulators, and couplers.