Location: Bldg. 216, Rm. C106
A variety of scanning probe techniques is widely used for imaging and manipulating nanoscale objects. To make high spatial resolution possible, these probes incorporate nanoscale or even atomically sharp features that can locally interact with the object of interest in a variety of ways; e.g. mechanically (AFM), electrically (STM) or optically (NSOM). However, these techniques employ comparably stiff probes and are typically limited to relatively large interaction forces. Most instruments also employ only a single probe at a time, further limiting the measurement and nanomanipulation capability. In a different approach, optical tweezers can be used to trap and manipulate microscale and mesoscale objects in three dimensions through a mechanical force exerted by the optical field itself. Micromete-scale objects can be manipulated with 0.1-nm precision and extremely small forces can be precisely measured, making optical tweezers particularly useful for studying interactions in biological systems. In addition, multiple objects can be trapped and manipulated simultaneously and independently when the light field is holographically controlled in situ by a computer.
Here we are enabling new nanoscale measurement and manipulation methods that combine the multiple probe flexibility and the small force measurement capability of Holographic Optical Tweezers (HOT) with the spatial precision of scanning probe techniques. These methods are based on a novel set of microfabricated tools that can be manipulated via HOT. Each tool will include a sharp working end for nanoscale spatial localization of the interaction region, and a larger, micrometer-sized handle perfectly matched for optical manipulation and interrogation. We envision working ends functionalized differently for various types of tip-sample interactions, and multiple tools operated simultaneously by the HOT system.