Fiber-integrated generation of optical-bottle beams using microcavity-cascade optical tweezers for particle manipulation
Phys. Rev. A 113, 023501 – Published 2 February, 2026
DOI: https://doi.org/10.1103/lsv1-mg83
Abstract
We present a fiber-integrated approach for generating optical-bottle beams based on a microcavity-cascade optical tweezers (MCOT) probe. A 650 nm laser excites the mode in a single-mode fiber through controlled core offset, and the resulting quadrupolar field undergoes multipath interference inside a thermally tapered microcavity. Internal reflections introduce phase shifts that form closed three-dimensional dark regions surrounded by high-intensity fringes, enabling stable optical-bottle beams. Finite-element simulations and experiments confirm the repeatable trapping and release of low-refractive-index particles in an aqueous environment, demonstrating robust three-dimensional confinement. The fabrication process of the composite fiber probe is straightforward and compatible with fiber-optic integration, providing a compact and tunable platform for particle manipulation. Owing to its simplicity, stability, and scalability, the proposed method offers potential for applications in optical trapping, microfluidics, and bioengineering.
