title: Modeling dispersive coupling and losses of localized optical and mechanical modes in optomechanical crystals.
abstract: Periodically structured materials can sustain both optical and mechanical excitations which are tailored by the geometry. Here we analyze the properties of dispersively coupled planar photonic and phononic crystals: optomechanical crystals. In particular, the properties of co-resonant optical and mechanical cavities in quasi-1D (patterned nanobeam) and quasi-2D (patterned membrane) geometries are studied. It is shown that the mechanical Q and optomechanical coupling in these structures can vary by many orders of magnitude with modest changes in geometry. An intuitive picture is developed based upon a perturbation theory for shifting material boundaries that allows the optomechanical properties to be designed and optimized. Several designs are presented with mechanical frequency approximately 1-10 GHz, optical Q-factor Qo > 107, motional masses meff approximately 100 femtograms, optomechanical coupling length LOM < 5 microm, and clampinig losses that are exponentially suppressed with increasing number of phononic crystal periods (radiation-limited mechanical Q-factor Qm > 107 for total device size less than 30 microm).
authors.affiliation: Thomas J Watson, Sr, Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125, USA. opainter@caltech.edu
authors.forename: Matt
authors.initials: M
authors.lastname: Eichenfield
authors.forename: Jasper
authors.initials: J
authors.lastname: Chan
authors.forename: Amir H
authors.initials: AH
authors.lastname: Safavi-Naeini
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Vahala
authors.forename: Oskar
authors.initials: O
authors.lastname: Painter
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D003460:Crystallization; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers