Journal Article
Modeling dispersive coupling and losses of localized optical and mechanical modes in optomechanical crystals
| 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 similar to 1-10 GHz, optical Q-factor Q(o) > 10(7), motional masses m(eff) approximate to 100 femtograms, optomechanical coupling length L-OM < 5 mu m, and clampinig losses that are exponentially suppressed with increasing number of phononic crystal periods (radiation-limited mechanical Q-factor Q(m) > 10(7) for total device size less than 30 mu m). (C) 2009 Optical Society of America |
Journal Name
Opt. Express
Publication Date
October, 2009
DOI
10.1364/OE.17.020078