We discuss studies on optical trapping dynamics of particles at different axial planes and effect of optical nonlinearity on the equilibrium position of stable trap under femtosecond pulsed excitation.
Here, we present experimental results of optical trapping of dielectric microparticles with structured laser beam created by computer-generated holograms using a spatial light modulator. We compared the trapping efficiencies with converging obstructed Gaussian and Gaussian beams.
In this paper, we present theoretical studies on nonlinear laser trapping of metal/dielectric core/shell nanoparticles using the generalized Lorenz-Mie theory. We discuss the effect of optical nonlinearity under femtosecond pulsed excitation including the effect of Fano-resonance.
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.
Recent theoretical and experimental results have shown how the trapping force/potential can be dramatically modulated due to optical and thermal nonlinearity. Compared with dielectrics, metals show even more interesting behavior (for example, trap-splitting, enhanced forward scattering, etc.) owing to higher-order optical nonlinearities. Hence, we present a comparison study for dielectric and metallic nanoparticles using generalized Lorenz-Mie theory.
Recently, the effect of optical nonlinearity in laser trapping has been investigated under pulsed excitation, and it was observed that the inclusion of nonlinearity significantly modulates trapping potential for metallic nanoparticles using dipole approximation. In this paper, we present theoretical studies on nonlinear laser trapping for silver nanoparticles using generalized Lorenz-Mie theory. We observe a reversal in the direction of asymmetry of potential well and splitting of the potential well due to nonlinear effects which is further modulated with an increase in laser power.
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