A firm grip with lasers: optimizing optical forces for trapping and deformation
Lead Research Organisation:
University of Glasgow
Department Name: School of Physics and Astronomy
Abstract
This project will investigate the forces involved in optical tweezers used to trap, hold and manipulate microscopic particles in a non-contact manner. We will explore how to trap particles as stiffly as possible - both for spheres and for more complex shapes such as nano-probes used to measure a surface profile.
We also believe this is closely linked to the question of how to control the shape of liquid droplets deformed using optical tweezers, and will explore the question of how to maximize the deforming forces on the droplet surface.
This project will use mathematical and numerical techniques to explore, understand and predict these effects, and gain a better understanding of how we can control and manipulate matter on a microscopic scale. In collaboration with experimental researchers, our goal is to make testable predictions and devise new and improved methods for optimal optical trapping and manipulation.
We also believe this is closely linked to the question of how to control the shape of liquid droplets deformed using optical tweezers, and will explore the question of how to maximize the deforming forces on the droplet surface.
This project will use mathematical and numerical techniques to explore, understand and predict these effects, and gain a better understanding of how we can control and manipulate matter on a microscopic scale. In collaboration with experimental researchers, our goal is to make testable predictions and devise new and improved methods for optimal optical trapping and manipulation.
Organisations
People |
ORCID iD |
| Jonathan Taylor (Primary Supervisor) | |
| Une Butaite (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509668/1 | 01/10/2016 | 30/09/2021 | |||
| 1804971 | Studentship | EP/N509668/1 | 03/10/2016 | 31/03/2020 | Une Butaite |
| Description | Throughout this research a new method for 2-dimensional hydrodynamic manipulation was developed. Hydrodynamic manipulation allows non-contact control of one or more target particles by controlling the fluid surrounding them, for example, with microfluidic channels. When attempting to control a specified target particle, most hydrodynamic manipulation techniques create large-scale fluid flows which inevitably disrupt any other particles in the medium, thus requiring extremely dilute samples for operation. The technique developed during this project makes use of optically trapped actuator particles to generate highly localised fluid flow, leaving the surrounding particles mostly undisturbed. To enable this technique a mathematical model was developed that allows estimating the required actuator motion based on the desired target particle motion. This model was then implemented in a feedback loop in numerical simulations and live experiments. Both simulations and experiments successfully confirmed that the method works. Results demonstrated include suppressing Brownian motion of particles of various sizes (1-10 microns in diameter) and various materials, simultaneous manipulation of up to three target particles, transportation of a single target particle across large distances, and orientation This research was presented at the Optical Manipulation Conference (Japan 2018) and published in Nature Communications under the title "Indirect optical trapping using light driven micro-rotors for reconfigurable hydrodynamic manipulation". A research visit to the University of Toronto was carried out with the aim of using optoelectronic tweezers (instead of optical tweezers) to control the actuating particles. However, it was found that optoelectronic tweezers exert long-range forces significantly large to interfere with the motion of target particles. Our hydrodynamic manipulation technique would therefore be limited to low-polarizability targets if used with optoelectronic tweezers. Methods for optimising optical trapping stiffness are being currently explored via computational simulations. |
| Exploitation Route | This work can be taken forward in academia and extended to 3-dimensional hydrodynamic manipulation (in combination with 3d imaging techniques). It is, at least in theory, possible to extend this model to 6-dimensional control (including three translational and three rotational degrees of freedom of the target particle), which would allow exact manipulation of more complex shapes. This hydrodynamic manipulation method might be employed by biologists to stabilise living cells over long periods of time without direct contact or damage. It can also be easily used to manipulate particles which cannot be manipulated in any other way due to their material composition. |
| Sectors | Other |