Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
Phys Rev Lett. 2011 Jul 15;107(3):037401. doi: 10.1103/PhysRevLett.107.037401. Epub 2011 Jul 11.
We present the first quantitative measurements of the torque exerted on a single gold nanorod in a polarized three-dimensional optical trap. We determined the torque both by observing the time-averaged orientation distribution and by measuring the dynamics of the rotational brownian fluctuations. The measurements are in good agreement with calculations, where the temperature profile around the hot nanorod gives rise to a reduced, effective viscosity. The maximum torque on a 60 nm×25 nm nanorod was 100 pN·nm, large enough to address single-molecule processes in soft and biological matter.
我们首次对置于偏振三维光阱中单个金纳米棒所受扭矩进行了定量测量。我们通过观察时间平均取向分布和测量旋转布朗涨落的动力学，确定了扭矩。测量结果与计算结果非常吻合，其中热纳米棒周围的温度分布导致有效粘度降低。在 60nm×25nm 的纳米棒上，最大扭矩为 100pN·nm，足以解决软物质和生物物质中的单分子过程。
