Eichenfield Matt, Chan Jasper, Safavi-Naeini Amir H, Vahala Kerry J, Painter Oskar
Thomas J Watson, Sr, Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125, USA.
Opt Express. 2009 Oct 26;17(22):20078-98. doi: 10.1364/OE.17.020078.
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).
周期性结构材料能够维持由几何形状所定制的光学和机械激发。在此，我们分析色散耦合的平面光子晶体和声子晶体的特性：光机械晶体。特别地，研究了准一维（图案化纳米梁）和准二维（图案化薄膜）几何结构中共振光学腔和机械腔的特性。结果表明，这些结构中的机械品质因数和光机械耦合会随着几何形状的适度变化而改变多个数量级。基于用于移动材料边界的微扰理论，形成了一种直观的图像，可用于设计和优化光机械特性。文中给出了几种设计，其机械频率约为1 - 10吉赫兹，光学品质因数Qo > 10⁷，运动质量meff约为100飞克，光机械耦合长度LOM < 5微米，并且随着声子晶体周期数的增加，夹持损耗呈指数级抑制（对于总器件尺寸小于30微米的情况，辐射限制的机械品质因数Qm > 10⁷）。
