title: Gigahertz All-Optical Modulation Using Reconfigurable Nanophotonic Metamolecules.
abstract: We report the design of reconfigurable metamolecules consisting a large array of nanowire featuring U-shaped cross section. These nanoscale metamolecules support colocalized electromagnetic resonance at optical frequencies and mechanical resonance at GHz frequencies with a deep-subdiffraction-limit spatial confinement (∼λ2/100). The coherent coupling of those two distinct resonances manifests a strong optical force, which is fundamentally different from the commonly studied forms of radiation forces, gradient forces, or photothermal induced deformation. The strong optical force acting upon the built-in compliance further sets the stage for allowing the metamolecules to dynamically change their optical properties upon the incident light. The all-optical modulation at the frequency at 1.8 GHz has thus been demonstrated experimentally using a monolayer of metamolecules. The metamolecules were conveniently fabricated using complementary metal-oxide-semiconductor-compatible metal deposition and nanoimprinting processes and thus offer promising potential in developing integrated all-optical modulator.
authors.affiliation: Mechanical Engineering Department and ‡Biomedical Engineering Department, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Biqin
authors.initials: B
authors.lastname: Dong
authors.affiliation: Mechanical Engineering Department and ‡Biomedical Engineering Department, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Xiangfan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Mechanical Engineering Department and ‡Biomedical Engineering Department, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhou
authors.affiliation: Mechanical Engineering Department and ‡Biomedical Engineering Department, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Mechanical Engineering Department and ‡Biomedical Engineering Department, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Hao F
authors.initials: HF
authors.lastname: Zhang
authors.affiliation: Mechanical Engineering Department and ‡Biomedical Engineering Department, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Cheng
authors.initials: C
authors.lastname: Sun
keywords: Metamolecules; all-optical modulation; gigahertz mechanical resonance; magnetic resonance; reconfigurable materials