Rotating manipulation of femtosecond optical tweezers based on optical wedge-lens group

Currently, research on optical tweezers technology predominantly focuses on single-trap optical tweezers, which have a limited controllable range. Multi-trap optical tweezers effectively address these limitations. This paper proposes a method for developing a dual-trap optical tweezers system utilizing basic optical elements. Two optical traps are created by reflecting a laser beam off the front and rear surfaces of a beam splitter. The transition between single-trap and dual-trap configurations is facilitated by a lens group, which allows for the adjustment of the distance between the two traps. Furthermore, by incorporating a rotatable optical wedge into the optical path, the optical trap can be rotated along an annular orbit of any radius. This study includes simulations and analyses of the effects of lens spacing, refractive index, and tilt angle on the rotational range of optical traps. An optical trapping experimental system was constructed, and its feasibility was demonstrated using polystyrene particles as the target objects.