title: Optical Switching Using Transition from Dipolar to Charge Transfer Plasmon Modes in Ge2Sb2Te5Bridged Metallodielectric Dimers.
abstract: Capacitive coupling and direct shuttling of charges in nanoscale plasmonic components across a dielectric spacer and through a conductive junction lead to excitation of significantly different dipolar and charge transfer plasmon (CTP) resonances, respectively. Here, we demonstrate the excitation of dipolar and CTP resonant modes in metallic nanodimers bridged by phase-change material (PCM) sections, material and electrical characteristics of which can be controlled by external stimuli. Ultrafast switching (in the range of a few nanoseconds) between amorphous and crystalline phases of the PCM section (here Ge2Sb2Te5(GST)) allows for designing a tunable plasmonic switch for optical communication applications with significant modulation depth (up to 88%). Judiciously selecting the geometrical parameters and taking advantage of the electrical properties of the amorphous phase of the GST section we adjusted the extinction peak of the dipolar mode at the telecommunication band (λ~1.55 μm), which is considered as the OFF state. Changing the GST phase to crystalline via optical heating allows for direct transfer of charges through the junction between nanodisks and formation of a distinct CTP peak at longer wavelengths (λ~1.85 μm) far from the telecommunication wavelength, which constitutes the ON state.
authors.affiliation: Department of Electrical and Computer Engineering, Florida International University, 10555 W Flagler St, Miami, Florida 33174, United States.
authors.forename: Arash
authors.initials: A
authors.lastname: Ahmadivand
authors.affiliation: Department of Electrical and Computer Engineering, Florida International University, 10555 W Flagler St, Miami, Florida 33174, United States.
authors.forename: Burak
authors.initials: B
authors.lastname: Gerislioglu
authors.affiliation: Department of Electrical and Computer Engineering, Florida International University, 10555 W Flagler St, Miami, Florida 33174, United States.
authors.forename: Raju
authors.initials: R
authors.lastname: Sinha
authors.affiliation: Department of Electrical and Computer Engineering, Florida International University, 10555 W Flagler St, Miami, Florida 33174, United States.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Karabiyik
authors.affiliation: Department of Electrical and Computer Engineering, Florida International University, 10555 W Flagler St, Miami, Florida 33174, United States.
authors.forename: Nezih
authors.initials: N
authors.lastname: Pala