Vortex-Pair Beam Optical Tweezer for Non-Spherical Particle Control
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Solution Overview
Problem
Existing optical tweezer systems struggle to precisely control the relative positions and directional rotation of non-spherical particles, such as rod-shaped particles, due to complexity and low controllability.
Innovation Solution
A vortex-pair beam based optical tweezer system utilizing a spatial light modulator to load different vortex pair phase diagrams, allowing for real-time manipulation of particles by regulating topological charges and off-axis distance, enabling precise control of particle positions and rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single vortex beam is used to trap particles, then the particle can be trapped and manipulated, but the relative positions of multiple particles cannot be precisely controlled and non-spherical particles cannot be rotated directionally
Solution Approach 1:
The patent divides a single vortex beam into two separate vortex beams with different topological charges (m1 and m2), creating distinct trapping regions. This segmentation allows independent control of multiple particles or control of non-spherical particle orientation, resolving the contradiction between control precision and system complexity by using a modular beam structure rather than a single complex system
Solution Approach 2:
The patent applies different topological charges (m1 ≠ m2) to different regions of the beam, creating locally differentiated trapping characteristics. The first vortex beam has topological charge m1 while the second has m2, allowing selective trapping and rotation control in different spatial regions, thereby achieving precise control of particle positions and orientations without requiring an entirely complex system
2Manufacturing precision
If vortex beams with different topological charges are used to trap multiple particles, then relative positions can be controlled, but the system becomes more complex
Solution Approach 1:
The patent uses a single optical tweezers system capable of generating multiple vortex beams with different topological charges to achieve multiple functions: trapping spherical particles at controlled relative positions, and rotating non-spherical particles directionally. This multi-functionality allows one system to replace what would traditionally require multiple separate systems, maintaining high precision while avoiding excessive complexity
Solution Approach 2:
The patent controls the trapping characteristics by adjusting parameters of the vortex beams, specifically the topological charges m1 and m2, and the off-axis distance a between the two vortices. By changing these parameters, the system can precisely control the relative positions of trapped particles and the rotation of non-spherical particles, achieving high manufacturing precision through parameter modulation rather than structural complexity
3Adaptability or versatility
If traditional optical tweezers are used, then simple particle trapping is achieved, but non-spherical particles cannot be rotated controllably
Solution Approach 1:
The patent introduces asymmetry in the beam structure by using two vortex beams with different topological charges (m1 ≠ m2) and an off-axis distance a between them. This asymmetric configuration creates differentiated trapping forces that can selectively rotate non-spherical particles in specific directions, thereby expanding the application range to include controllable rotation of non-spherical particles while maintaining reasonable operational difficulty through structured beam design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves high precision and stability in controlling the relative positions and rotations of particles, expanding the application range of optical tweezers to include irregularly shaped particles like rod-shaped ones, with controllable directional rotation and adjustable speed.
Implementation Method 1
the vortex beam carries orbital angular momentum during propagation, so angular momentum and linear momentum will be exchanged between the vortex beam and the particle
Implementation Method 2
One is the gradient force, which refers to the acting force on the particle due to refraction, and the direction points to the focus center of the beam
Implementation Method 3
the other is a scattering force, which refers to the acting force on the particle due to reflection of the beam
Data Source
AI summary
The present disclosure discloses a vortex-pair beam based optical tweezer system, including a laser device (1), a collimating beam expanding system, a spatial light modulator (6), a confocal beam shrinking system, a sample table (12), and an observation unit arranged according to a light path. The spatial light modulator (6) continuously loads different vortex-pair beam phase diagrams in real time, and manipulates and rotates a particle in real time by using a single vortex-pair beam. The optical tweezer system can realize precise regulation, control, and positioning of two spherical particles at any positions in a plane, and any controllable rotation operation of a rod-shaped particle in the plane, which makes application objects of the optical tweezer system richer, and effectively solves the problem that the rod-shaped particle is difficult to be controlled by the existing optical tweezer system.