Tunable optical switching in the near-infrared spectral regime by employing plasmonic nanoantennas containing phase change materials

Abstract

We propose the design of switchable plasmonic nanoantennas (SPNs) that can be employed for optical switching in the near-infrared regime. The proposed SPNs consist of nanoantenna structures made up of a plasmonic metal (gold) such that these nanoantennas are filled with a switchable material (vanadium dioxide). We compare the results of these SPNs with inverted SPN structures that consist of gold nanoantenna structures surrounded by a layer of vanadium dioxide (VO) on their outer surface. These nanoantennas demonstrate switching of electric-field intensity enhancement (EFIE) between two states (On and Off states), which can be induced thermally, optically or electrically. The On and Off states of the nanoantennas correspond to the metallic and semiconductor states, respectively of the VO film inside or around the nanoantennas, as the VO film exhibits phase transition from its semiconductor state to the metallic state upon application of thermal, optical, or electrical energy. We employ finite-difference time-domain (FDTD) simulations to demonstrate switching in the EFIE for four different SPN geometries - nanorod-dipole, bowtie, planar trapezoidal toothed log-periodic, and rod-disk - and compare their near-field distributions for the On and Off states of the SPNs. We also demonstrate that the resonance wavelength of the EFIE spectra gets substantially modified when these SPNs switch between the two states.

Tunable and reconfigurable metasurfaces and metadevices

“…When phase changes between two states, VO 2 is accompanied by significant changes in optical and electronic properties. It is a suitable functional material for many optoelectrical applications, such as active polarizer in near-infrared region 95 , tunable absorber 97,187,188 , tunable switching 189,190 , beam steering 191 , switchable quarter wave plate (QWP) in THz 96,192 , and active nanoantennas for tuning THz resonance [193][194][195] . By hybridizing metasurfaces with VO 2 , an ultrathin switchable THz QWP with a switching range of 34 GHz was experimentally demonstrated 96 .…”

Stimuli-Responsive Phase Change Materials: Optical and Optoelectronic Applications

“…Exploiting the Kerker condition, in which induced magnetic and electric dipoles interfere either destructively or constructively in the forward/backward directions, and under the application of a stimulus that changes the phase of GST from amorphous to crystalline, the radiation pattern switches dramatically from unidirectional to dipole-like. An alternative way to tune the radiation properties of PCM-based optical antennas in the near-infrared was indicated by Savalyia et al [ 93 ]. The idea is to replace a portion of the volume of plasmonic antennas with a PCM (in the proposed configuration, VO 2 ) in stark contrast with the most common approach in which VO 2 is in proximity, but in the outside body of the nanoantenna.…”

Non-Uniform Narrow Groove Plasmonic Nano-Gratings for SPR Sensing and Imaging

“…This FDTD software incorporates dispersion models such as Drude, Lorentz-Drude, and Debye models. In our simulations, the relative permittivity of gold was modelled using Lorentz-Drude dispersion model from literature [47]. The polarization of incident plane wave radiation was taken as TM polarization, in all the FDTD simulations employed for determining the reflectance spectra for the proposed nano-gratings.…”