Formation of a three-dimensional bottle beam via an engineered microsphere

In this work, we propose a novel approach to produce three-dimensional (3D) optical trapping with sub-wavelength size through an engineered microsphere, under linear polarization states of an incident light. The engineered microsphere is designed to contain the segmented regions of diffractive patterns and made by focused ion beam fabrication. We simulate and experimentally characterize the focus performance of the engineered micro-sphere. The emitted light field from the exit surface of the engineered microsphere forms a pair of axially arranged focused beams, and they are connected with a continuous optical field embracing a 3D optical null at the center, forming the so-called optical bottle beam. Experimental results and numerical simulation are in good agreement. Such micro-optics can be used for precise and localized optical trapping. (C) 2021 Chinese Laser Press

Automated summary

This work introduces a novel approach to generate sub-wavelength size 3D optical trapping through an engineered microsphere, containing diffractive patterns and fabricated by focused ion beam. The emitted light field forms a pair of axially arranged focused beams connected by a continuous optical field, creating an optical bottle beam with a 3D optical null at the center. Experimental results and numerical simulations are in good agreement, demonstrating precise and localized optical trapping capabilities.