Optical trapping forces on nanoparticles in nonlinear medium under femtosecond pulsed excitation

Under short pulsed excitation, depending on the nonlinear refractive index of the particle and the surrounding medium, optical nonlinearity plays a significant role in modulating optical forces on particles. Here, we explore the trapping forces experienced by dielectric nanoparticles in a highly nonlinear medium taking into account nonlinear propagation of Gaussian beam.