Enhancement of trapping efficiency by utilizing a hollow sinh-Gaussian beam.

Propagation properties and optical forces upon a Rayleigh dielectric sphere for a newly proposed hollow sinh-Gaussian beam (HsGB) are intensively investigated. In view of the targeted laser beam's unique tight focusing properties that a significantly sharp, peak-centered, and adjustable intensity distribution would be produced in the focal vicinity, the tightly focused HsGB could be exploited to trap and manipulate nano-sized dielectric spheres with high-refractive index in the focal region. The interesting and meaningful features for the novel HsGB mainly include that, compared with the conventional fundamental Gaussian beams under the same optical power, the tightly focused HsGB has much higher intensity gradient and deeper potential well through optimizing targeted laser beam's parameters. Theretofore, the novel HsGB optical tweezers could drastically enhance its trapping efficiency. Finally, the trapping stability conditions are discussed in detail. The analytical and numerical results obtained here could provide a directive suggestion for researchers in optimizing experimental parameters in constructing a novel HsGB tweezers and making use of a HsGB.