Optical binding in nanoparticle assembly: Potential energy landscapes
Optical binding in nanoparticle assembly: Potential energy landscapes
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纳米粒子组装中的光学结合：势能景观
DOI：
10.1103/physreva.78.043805
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发表时间：
2008
影响因子：
2.9
通讯作者：
D. Andrews
中科院分区：
文献类型：
--
作者：
Justo J Rodriguez;L. Romero;D. Andrews
光学结合是由微米和纳米颗粒的系统表现出的光学机械效应，适当地用非共振激光照射。物理上不同于驻波和其他形式的全息光学陷阱，这种现象是由于粒子间与各个辐射模式的耦合而产生的，从而导致对Casmir-Polder相互作用的光学诱导修改。为了更好地理解这种机制如何导致所观察到的组装和纳米粒子图案的形成，我们开发了一个理论，在光诱导的能量景观表现出三维形式的势能场。它详细示出的定位和局部能量最大值和最小值的大小取决于每个粒子对的配置，相对于激光的偏振和波矢量。该分析揭示了如何定位的局部极小值确定的能量最有利的位置，添加第三个粒子到每个平衡对。它还演示了如何这样的结果，除了微妙地修改能源景观，这将反过来，确定进一步的粒子添加的最佳位置。因此，这一发展代表了理论的严格和一般性的表述，为充分理解基于光学结合的纳米颗粒组装铺平了道路。
Optical binding is an optomechanical effect exhibited by systems of micro- and nanoparticles, suitably irradiated with off-resonance laser light. Physically distinct from standing-wave and other forms of holographic optical traps, the phenomenon arises as a result of an interparticle coupling with individual radiation modes, leading to optically induced modifications to Casmir-Polder interactions. To better understand how this mechanism leads to the observed assemblies and formation of patterns in nanoparticles, we develop a theory in terms of optically induced energy landscapes exhibiting the three-dimensional form of the potential energy field. It is shown in detail that the positioning and magnitude of local energy maxima and minima depend on the configuration of each particle pair, with regards to the polarization and wave vector of the laser light. The analysis reveals how the positioning of local minima determines the energetically most favorable locations for the addition of a third particle to each equilibrium pair. It is also demonstrated how the result of such an addition subtly modifies the energy landscape that will, in turn, determine the optimum location for further particle additions. As such, this development represents a rigorous and general formulation of the theory, paving the way toward full comprehension of nanoparticle assembly based on optical binding.