title: Slot-mode-coupled optomechanical crystals.
abstract: We present a design methodology and analysis of a cavity optomechanical system in which a localized GHz frequency mechanical mode of a nanobeam resonator is evanescently coupled to a high quality factor (Q > 10(6)) optical mode of a separate nanobeam optical cavity. Using separate nanobeams provides flexibility, enabling the independent design and optimization of the optics and mechanics of the system. In addition, the small gap (≈ 25 nm) between the two resonators gives rise to a slot mode effect that enables a large zero-point optomechanical coupling strength to be achieved, with g/2 π > 300 kHz in a Si(3)N(4) system at 980 nm and g/2 π ≈ 900 kHz in a Si system at 1550 nm. The fact that large coupling strengths to GHz mechanical oscillators can be achieved in Si(3)N(4) is important, as this material has a broad optical transparency window, which allows operation throughout the visible and near-infrared. As an application of this platform, we consider wide-band optical frequency conversion between 1300 nm and 980 nm, using two optical nanobeam cavities coupled on either side to the breathing mode of a mechanical nanobeam resonator.
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203, USA. mdavanco@nist.gov
authors.forename: Marcelo
authors.initials: M
authors.lastname: Davanço
authors.forename: Jasper
authors.initials: J
authors.lastname: Chan
authors.forename: Amir H
authors.initials: AH
authors.lastname: Safavi-Naeini
authors.forename: Oskar
authors.initials: O
authors.lastname: Painter
authors.forename: Kartik
authors.initials: K
authors.lastname: Srinivasan