Improved optical fiber tweezers using 3D printed Fresnel lenses (Conference Presentation)

A new approach of a highly efficient counter propagating optical fiber based tweezers using 3D printed Fresnel lenses at the fiber facets will be presented. In contrast to conventional fiber tip tweezers the emitted beams of the Fresnel lens fibers are converging resulting in a significantly enhanced trapping efficiency in both axial and transverse direction. The used polymer diffractive Fresnel lens structures are fabricated by femtosecond two photo lithography using a commercial system. The measured trapping efficiencies are found to be up to 90 times higher than for similar results using chemically wet-etched fiber tips. A short outlook on further concepts of enhanced optical fiber tweezers based on 3D diffractive structures will also be given.