Design and Synthesis of Microscale Opto-Magnetic Trapping Handles

Joseph L. Lawson, Ph.D. Defense

Friday, January 22, 2016
8:30 a.m.

Hopeman 224

Opto-Magnetic Trapping (OMT) is a novel micromanipulation technology capable of translating particles with nanometer precision and producing forces on the order of pico-Newtons. OMT combines the benefits of optical trapping (OT) to manipulate handle particles in translational directions and magnetic trapping (MT) to provide rotational control. This combined manipulation technology shows promise for applications ranging from novel single molecule force spectroscopy to advanced manufacturing of smart micro or nano structures. Successful OMT requires handles containing material properties amenable to both OT and MT individually.

Since these material properties are traditionally exclusive, novel anisotropic handles must be synthesized to accommodate both micromanipulation technologies.

This body of research advances the state of the art in micromanipulation technology by addressing the fundamental material incompatibility issues associated with OMT. Novel micro-scale "patchy" handle particles were fabricated using a glancing angle deposition (GLAD) process. Due to their composite design combining dielectric and ferromagnetic materials, these particles successfully demonstrated OMT manipulation. These particles, along with the developed GLAD fabrication process, improve upon the current state of the art by enabling the robust synthesis of a wider range of particle sizes. Furthermore, the magnetic moments of these particles can be more accurately controlled over a wider range including producing magnetic moments grater than is capable with current techniques. A thorough numerical simulation was also conducted to identify the variation of OT performance of these patchy particles with respect to standard dielectric-only OT handles. While variations in trapping location do exist, they were found to be within an acceptable range for OMT applications and are still capable of manipulation with nanometer precision.