  The rapid loading and manipulation of microspheres in optical trap is
important for its applications in optomechanics and precision force sensing. We
investigate the microsphere behavior under coaction of a dual-beam fiber-optic
trap and a pulse laser beam, which reveals a launched microsphere can be
effectively captured in a spatial region. A suitable order of pulse duration
for launch is derived according to the calculated detachment energy threshold
of pulse laser. Furthermore, we illustrate the effect of structural parameters
on the launching process, including the spot size of pulse laser, the vertical
displacement of beam waist and the initial position of microsphere. Our result
will be instructive in the optimal design of the pulse-laser-assisted optical
tweezers for controllable loading mechanism of optical trap.
