Material Independent Long Distance Pulling, Trapping, and Rotation of Fully Immersed Multiple Objects with a Single Optical Set-up

TL;DR

This paper introduces a novel optical tractor beam capable of long-distance manipulation, rotation, and trapping of multiple fully immersed objects using superimposed Bessel beams with different frequencies, eliminating manual phase adjustments.

Contribution

It presents a new active tractor beam design that enables controlled movement and rotation of multiple immersed objects with a single setup, overcoming previous limitations.

Findings

Demonstrated stable long-distance levitation and manipulation of multiple objects

Achieved controlled rotation and 3D trapping using superimposed Bessel beams

Proposed conditions for increasing target binding regions for different object sizes and shapes

Abstract

Optical pulling with tractor beams is so far highly dependent on (i) the property of embedding background or the particle itself , (ii) the number of the particles and/or (iii) the manual ramping of beam phase. A necessary theoretical solution of these problems is proposed here. This article demonstrates a novel active tractor beam for multiple fully immersed objects with its additional abilities of yielding a controlled rotation and a desired 3D trapping. Continuous and stable long distance levitation, controlled rotation and 3D trapping are demonstrated with a single optical set-up by using two coaxial, or even non-coaxial, superimposed non-diffracting higher order Bessel beams of reverse helical nature and different frequencies. The superimposed beam has periodic intensity variations both along and around the beam-axis because of the difference in longitudinal wave-vectors and beam orders, respectively. The difference in frequencies of two laser beams makes the intensity pattern move along and around the beam-axis in a continuous way without manual ramping of phase, which allows for either linear motion (forward or backward) or angular movement (clockwise or anticlockwise) of fully immersed multiple particles. As a major contribution, the condition for increasing the target binding regions is also proposed to manipulate multiple immersed objects of different sizes and shapes.