All-Fiber Active Tractor Beam Generator and its Application

We propose and demonstrate an all-fiber probe to generate an active tractor beam by changing the gradients of optical intensity distributions. We grind the tip of a seven-core fiber (SCF) into a truncated hexagonal pyramid shape to integrate three equivalent two-core fiber optical tweezers in an SCF. Three optical tweezers produce three trapping locations along the fiber main axis. By adjusting and controlling the incident laser power in each core, we may perform multiple functions, including microparticles optical trapping, long-distance attraction, bidirectional transportation, and axial-direction position controllable adjustment. The proposed all-fiber active tractor beam generator is convenient to integrate and low cost. The all-fiber probe has the compatibility of optical tweezers and optical tractor beams. The increased effective range of optical pull broadens the scope of feasible optical trapping and will pave the way towards more efficient light-powered miniature machines, tools, and applications.