title: Ultralow-energy and high-contrast all-optical switch involving Fano resonance based on coupled photonic crystal nanocavities.
abstract: We experimentally and theoretically clarified that a Fano resonant system based on a coupled optical cavity has better performance when used as an all-optical switch than a single cavity in terms of switching energy, contrast, and operation bandwidth. We successfully fabricated a Fano system consisting of doubly coupled photonic-crystal (PhC) nanocavities, and demonstrated all-optical switching for the first time. A steep asymmetric transmission spectrum was clearly observed, thereby enabling a low-energy and high-contrast switching operation. We achieved the switching with a pump energy of a few fJ, a contrast of more than 10 dB, and an 18 ps switching time window. These levels of performance are actually better than those for Lorentzian resonance in a single cavity. We also theoretically investigated the achievable performance in a well-designed Fano system, which suggested a high contrast for the switching of more than 20 dB in a fJ energy regime.
authors.affiliation: NTT Nanophotonics Center, NTT Corp, 3-1 Morinosato Wakamiya Atsugi, Kanagawa 243-0198, Japan. nozaki.kengo@lab.ntt.co.jp
authors.forename: Kengo
authors.initials: K
authors.lastname: Nozaki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Shinya
authors.forename: Shinji
authors.initials: S
authors.lastname: Matsuo
authors.forename: Tomonari
authors.initials: T
authors.lastname: Sato
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kuramochi
authors.forename: Masaya
authors.initials: M
authors.lastname: Notomi
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation*; D017785:Photons; D012031:Refractometry / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*