The advances in nanotechnology have intensified the need for tools that can characterize newly synthesized nano materials.  A powerful approach to address this need is the combination of scanned probe techniques with optical illumination, which combines the nanoscopic resolution provided by a sharp tip with the chemical recognition provided by optical spectroscopy. A new and powerful technique in this direction is photo-induced force microscopy (PiFM), which enables spectroscopic probing of materials with a spatial resolution under 10 nm.

In PiFM, the response of the optically excited sample is probed directly in the near-field by reading out the time-integrated force between the tip and the sample. Because the magnitude of the force is dependent on the photo-induced polarizability of the sample, PiFM exhibits spectroscopic sensitivity. With very high spatial resolution even under ambient conditions, PiFM enables the real-space imaging along with chemical recognition of a wide range of nano materials, from semi-conducting nanoparticles to polymer thin films to sensitive measurements of single molecules.

In the talk, the principles and the basic components of the PiFM will be presented. The nanoscale imaging applications and the spectroscopic sensitivity of the technique on various samples (polymer blends, nano-fibers, polypeptides, block copolymers, 2D materials, etc.) will be highlighted.

Bio:

Dr. Park is the CEO of Molecular Vista, which he co-founded with Prof. Kumar Wickramasinghe (UC Irvine, formerly of IBM) in 2011 to provide research and industrial tools for rapid and nanoscale imaging with chemical identification.  Dr. Park has more than 25 years of experience of industrial R&D, engineering, marketing and sales, and operations.  Dr. Park co-founded Park Scientific Instruments (PSI), which was one of the first commercial companies to develop and sell scanning tunneling microscopes (STM) and atomic force microscopes (AFM).  Dr. Park earned a Ph.D. in Applied Physics from Stanford University and BA in Physics from Pomona College.