Active directional switching of surface plasmon polaritons using a phase transition material

Abstract

Active switching of near-field directivity, which is an essential functionality for compact integrated photonics and small optoelectronic elements, has been challenging due to small modulation depth and complicated fabrication methods for devices including active optical materials. Here, we theoretically and experimentally realize a nanoscale active directional switching of surface plasmon polaritons (SPPs) using a phase transition material for the first time. The SPP switching device with noticeable distinction is demonstrated based on the phase transition of vanadium dioxide (VO2) at the telecom wavelength. As the insulator-to-metal phase transition (IMT) of VO2 induces the large change of VO2 permittivity at telecom wavelengths, the plasmonic response of a nanoantenna made of VO2 can be largely tuned by external thermal stimuli. The VO2-insulator-metal (VIM) nanoantenna and its periodic array, the VIM metagrating, are suggested as optical switches. The directional power distinction ratio is designed to change from 8.13:1 to 1:10.56 by the IMT and it is experimentally verified that the ratio changes from 3.725:1 to 1:3.132 as the VIM metagratings are heated up to 90 °C. With an electro-thermally controllable configuration and an optimized resonant design, we expect potential applications of the active switching mechanism for integrable active plasmonic elements and reconfigurable imaging.

Metasurfaces Based on Phase-Change Material as a Reconfigurable Platform for Multifunctional Devices

“…Several papers have reported VO 2 -based controllable plasmonic modulators that can be tuned by external stimuli [ 75 , 76 , 78 ]. A grating-based metasurface that exploits the phase transition property of VO 2 has been developed as an active switch of surface plasmon polaritons (SPPs) at the telecom wavelength ( Figure 10 a) [ 79 ]. Illumination by of a monochromatic laser normal to the surface generated two SPPs ( Figure 10 b) [ 79 ].…”

“…Theoretical and experimental results confirmed that thermal stimuli can induce active and reversible switching of SPPs. The scattering direction of the nanograting was switched depending on the applied temperature; this phenomenon may cause the phase-transition behavior of VO 2 [ 79 ].…”

“…( e ) Rewritable memory effect of the metadevice; ( f – i ) AIST-based metadevice: ( f ) A representation of an AIST-based color filter; ( g ) The generated colors using an AIST-integrated metafilter; ( h ) Resolution of created nanopixels on AIST using CAFM; ( i ) I – V curves of the AIST film obtained by CAFM. ( a , b ) are adapted from [ 79 ], with permission from © 2017 Nature Publishing Group; ( c – e ) are adapted from [ 80 ], with permission from © 2016 Nature Publishing Group; and ( f – i ) are adapted from [ 71 ], with permission from © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.…”

Using phase-change materials to switch the direction of reflectionless light propagation in non-PT-symmetric structures

“…Achieving unidirectional reflectionless propagation is important for several key applications in photonic circuits such as optical network analyzers [15,19]. In addition, switching of the direction of reflectionless light propagation could be essential for building compact optoelectronic devices, for reducing the size of optical systems, and for developing reconfigurable optical components [31][32][33]. This could be achieved by using materials with tunable optical properties such as phase-change materials.…”

“…This phenomenon is commonly referred to as superscattering. Switching between the cloaking and enhanced scattering states could be essential for building compact optoelectronic devices, for reducing the size of optical systems, and for developing reconfigurable optical components [67][68][69][70][71][72][73][74][75][76][77][78][79]. Such switching between the enhanced scattering and invisibility cloaking regimes has been demonstrated using nonlinear materials [70] and quantum emitters [71].…”