Joseph Herzog
Speciality: Plasmonic Nano-Optics
Phone: (479) 575-4217
Office: Physics 237


The field of plasmonics has become a topic of interest for understanding more optical physics at the nanoscale and due to its use in various applications including detection and sensing at the nanoscale, plasmonically enhanced spectroscopies, improved photovoltaics, and other optoelectronic devices. Nanoscale features and geometries of plasmonic structures are key for maximizing the optical enhancement of the devices. One of the most common nanofabrication process uses electron beam lithography (EBL), which can fabricate nanostructures down to ~40 nm, however, trying to make nanoscale features any smaller than this is difficult to do with EBL alone. Here we make use of a relatively new, previously developed, self-aligned process to overcome this limit in order to make nanogaps, and even other metal features, on the order of 2 – 10 nm! Fabricating truly nanoscale gaps allows for increased and more localized plasmonically enhanced electric fields. Computational electromagnetics simulations are used to provide valuable information about the optical response of the structures. The models will also be used to confirm optical response and optimize the nanostructure designs and architectures. In addition to using these structures for plasmonically enhanced applications, such structures can also contribute toward a better understanding of the physics of the growing field of plasmonics. Furthermore, optimize the nano-fabrication process, can also contribute to advancements in other nano-science fields, in addition to nano-optics. My research program fabricates these nanostructures, models them with computational electromagnetics, and characterizes the devices with optical spectroscopies.



  • Nano-Fabrication: Researcher in group fabricate metal nanostructures with features that can be smaller than structures fabricated with the more-common electron beam lithography (EBL) technique. Typically the smallest feature with EBL alone can reach about 40 nm. In our lab we use EBL combined with a recently developed self-aligned technique which can make truly nanoscale features than can be less than 10 nm.
  • Computational Electromagnetics: Modeling optics (electromagnetic waves) with a finite element method has proven to be extremely accurate. We use this tool to help design and analyze plasmonic nanostructure. Resent developments in computational performance enables complex and robust calculations and modeling.
  • Optical Characterization: Once fabricated, our group with study the optical properties of the plasmonic nanostructures with various spectroscopic techniques in order to confirm our design and build towards more useful and powerful structures.