Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
Opt Lett. 2011 Apr 15;36(8):1497-9. doi: 10.1364/OL.36.001497.
A method is described for measuring the potential energy of nanoparticles in an optical trap by trapping an ensemble of particles with a focused laser beam. The force balance between repulsive osmotic and confining gradient-force pressures determines the single-particle trapping potential independent of interactions between the particles. The ensemble nature of the measurement permits evaluation of single-particle trapping energies much smaller than kT. Energies obtained by this method are compared to those of single-particle methods as well as to theoretical calculations based on classical electromagnetic optics.
介绍了一种通过用聚焦激光束捕获粒子的方法来测量光学陷阱中纳米粒子的势能的方法。排斥渗透压和约束梯度力之间的力平衡决定了单个粒子的捕获势，而与粒子之间的相互作用无关。该测量的集合性质允许评估比 kT 小得多的单个粒子捕获能量。通过该方法获得的能量与基于经典电磁光学的单个粒子方法和理论计算的能量进行了比较。
