Measurements of Optical Trapping Efficiency for Micron-Sized Dilectric Particles in Various Surrounding Media

Abstract

The maximum axial trapping efficiency Q_max has been measured in water, ethanol, butanol and octanol for polystyrene latex spheres having a diameter of 2-15 μm. The effects of the diameter of the particle as well as the refractive index and the viscosity of surrounding medium have been investigated.For particles of d≥7 μm, Q_max is almost independent of particle size, while it decreases as the diameters decrease to d≤5 μm. It is also noted that Q_maxis affected by the viscosity rather than the refractive index of the surrounding medium.