Santosh Devasia

Mechanical Engineering

Applied research has focused on the use of inversion-based approaches to solve challenges in nano (and sub-nano) scale precision positioning needed in scanning probe microscopes such as the atomic force microscope (AFM) and the scanning tunneling microscope (STM). It is noted that the AFM and STM are key enabling tools in the nano area; therefore the current work aimed at increasing their throughput will have a significant impact on the real-time investigation and manipulation of nano-scale and sub-nano-scale phenomena. For example, the inability to precisely position an AFM probe (at high speed) over a cell surface has traditionally limited the ability to image time-varying dynamics of cellular processes. In particular, lack of precision positioning (due to movement-induced vibration) leads to excessive forces on the cell surface (as the probe digs into the cell) and causes sample damage. Therefore, current AFM imaging of cells is limited to low operating speeds. Our research group was the first to demonstrate (experimentally) that feedforward techniques can effectively compensate for movement-induced vibrations in Scanning Probe Microscopes. Thereby, we showed that feedforward inputs could be used to increase the operating speed of Scanning Probe Microscopes. See website for further information.