In contrast to many micromanipulation and microassembly techniques, optical tweezers (OT) are non-contact and are fully capable of 3D positioning. While OT have been used extensively for the ultra-precise measurement of small biomechanical forces and displacements, more recently, OT have been proposed for applications such as cell sorting, tissue engineering, and micro/nano fabrication, which all require larger translation distances and stronger forces. In these applications, manipulation speed is a key specification, but the majority of OT systems do not have the ability to reach the high velocities necessary to compete with other micromanipulation techniques in terms of throughput. In order to create faster OT systems, it is essential to understand the factors that limit the maximum manipulation speeds for different objects. Here, we present our measurements of the maximum lateral transport speeds of polystyrene, gold, and silver spheres ranging from 100 nm to 5 µm in diameter as a function of trapping beam power over a long translation distance of >0.5 mm. In particular, we investigate the behavior at high laser powers, beyond the traditional linear relationship between laser power and maximum manipulation velocity that is predicted by the balance of Stokes’ drag and optical gradient forces. We find that the nonlinear relationship between laser power and maximum velocity depends on the particle size and material, and may be caused by different factors, such as mechanical vibrations or thermal effects. Furthermore, to our knowledge, we demonstrate the fastest recorded object manipulation speed achieved using optical tweezers of 0.22 mm·s-1.
Jeffrey E. Melzer and Euan McLeod, "High velocity micro- and nano-particle optical manipulation (Conference Presentation)," Proc. SPIE 10549, Complex Light and Optical Forces XII, 105491E (Presented at SPIE OPTO: February 01, 2018; Published: 14 March 2018); https://doi.org/10.1117/12.2288582.5751529327001.
Conference Presentations are recordings of oral presentations given at SPIE conferences and published as part of the conference proceedings. They include the speaker's narration along with a video recording of the presentation slides and animations. Many conference presentations also include full-text papers. Search and browse our growing collection of more than 12,000 conference presentations, including many plenary and keynote presentations.