An Analysis for Optical Trapping Force in Single Beam Optical Tweezers

By means of single beam tracing method,the force of micro-beam exerting to microscopic particles is analyzed in the condition of geometrical optics approximation.The effects of laser micro-beam on optical trapping force are introduced.Numerical results show that not only the relative refraction index has an important effect on optical trapping force,but also the optical waist has one,too.Furthermore,the wavelength of laser and the size of microscopic particles have a lesser effect on optical trapping force.