In this talk, I will present recent progress in my research lab housed in the Center for High Technology Materials. The first part will focus on gap plasmon-enabled physical and chemical phenomena. In particular, the pitfall that results from ignoring chemical transformation in analyzing strong coupling and polariton states will be emphasized. In the second part, I will discuss results of scattering-type scanning near-field optical microscopy (s-SNOM), which achieve spatial resolution on the order of 10 nm independent of excitation wavelength. Generally, the sharpness of an atomic force microscope (AFM) tip, which serves as an optical antenna, is believed to determine the spatial resolution of s-SNOM. Interestingly, our experimental results show that the optical spatial resolution can be significantly better than the corresponding force images. Our observations indicate that localization of the field on the sample and detection polarization can play a role such that the optical resolution surpasses the topographic resolution of the AFM tip.  We have recently applied the s-SNOM technique for imaging vibrational modes of polymeric materials in real-space as well as for probing intersubband polaritons on individual infrared antenna. More recently, the technique has been used to discover hierarchical self-assembly of nanoscale domains in polymer blends, and these results will be discussed time permitting.  

Biography:

Dr. Habteyes received his B.S. and M.S. degrees in Chemistry from Addis Ababa University in 1997 and 2000, and his Ph.D. in Chemistry from the University of Arizona in 2008 working with Prof. Andrei Sanov. He was a postdoctoral fellow at the University of California at Berkeley and Lawrence Berkeley National Laboratory from 2008 to 2012 working with Prof. Stephen Leone and Prof. Paul Alivisatos.  He started his faculty position at the University of New Mexico in August 2012, and has been promoted to associate professor with tenure since July 2018. His research interest includes near-field microscopy, plasmonics, nanophotonics, surface photochemistry and interface properties.