CNR-Istituto per i Processi Chimico-Fisici, I-98158 Messina, Italy.
ACS Nano. 2010 Dec 28;4(12):7515-23. doi: 10.1021/nn1018126. Epub 2010 Dec 2.
Brownian motion is a manifestation of the fluctuation-dissipation theorem of statistical mechanics. It regulates systems in physics, biology, chemistry, and finance. We use graphene as prototype material to unravel the consequences of the fluctuation-dissipation theorem in two dimensions, by studying the Brownian motion of optically trapped graphene flakes. These orient orthogonal to the light polarization, due to the optical constants anisotropy. We explain the flake dynamics in the optical trap and measure force and torque constants from the correlation functions of the tracking signals, as well as comparing experiments with a full electromagnetic theory of optical trapping. The understanding of optical trapping of two-dimensional nanostructures gained through our Brownian motion analysis paves the way to light-controlled manipulation and all-optical sorting of biological membranes and anisotropic macromolecules.
布朗运动是统计力学中的涨落耗散定理的一种表现。它调节着物理、生物、化学和金融等领域的系统。我们使用石墨烯作为原型材料，通过研究光捕获石墨烯薄片的布朗运动，在二维空间中揭示涨落耗散定理的结果。由于光学常数各向异性，这些薄片与光的偏振方向正交。我们解释了光阱中的薄片动力学，并从跟踪信号的相关函数中测量力和扭矩常数，同时将实验与光捕获的全电磁理论进行比较。通过对二维纳米结构的布朗运动分析获得的光捕获理解，为生物膜和各向异性大分子的光控操纵和全光分选铺平了道路。
