“Organic and Organometallic Nonlinear Optical Materials“
Abstract:
The Materials and Manufacturing Directorate of the Air Force Research Laboratory has been working on the development of photonic materials for many years now. The presentation will briefly highlight the development of structured optical materials. We will then focus more on the development of nonlinear optical materials for several applications including light manipulation and laser source materials. In particular a deeper dive into the development of organic and organometallic nonlinear optical materials will be explored. Due to their ease of modification several classes of dyes have been synthesized and studied to form structure property relationships. We have looked at porphyrins and phthalocyanines, platinum phenylacetylenes, organic two photon absorbing dyes (AFX), and modified platinum two photon absorbing dyes. With small changes in structure these dyes have provided large amounts of data on the photophysical properties of the dyes to build the structure property relationship portfolio. The effects of high concentration on the photophysical properties of a nonlinear material have been of interest for some time in our group and it is well known in the literature that for a two-photon absorbing dye to be the most effective, high concentrations are needed. Recently efforts have been made to study the effects of incorporating a dye into a solid matrices consisting of polyurethane, epoxy, or sol gel at high concentration to better understand the constraints this environment has on a given material. In general results reveal the formation of excimers (excited state dimers) with an increase in concentration. Excimers may form from either the singlet excited state or the triplet excited state depending on the molecule and provide a competitive pathway for deactivation of the excited state back to the ground state. The formation of the excimer was found to lead to a significant quenching effect that will reduce nonlinear performance of this material. Understanding and mitigating excimer formation is an active area of research in our laboratory and will be discussed further.
Biography:
Dr. Joy E. Haley is recognized as a key leader in the development of optical materials for personnel, tactical, and space systems for the Air Force Research Laboratory, Materials & Manufacturing Directorate (AFRL/RX) and the Department of Defense (DoD). Her reputation was earned as a result of outstanding technical leadership as a senior chemist in the Photonic Materials Branch, leading a diverse team pertaining to organic nonlinear optical materials. In this role, Dr. Haley is responsible for setting the overall technical strategy, research quality, and resource execution/allocation in this area. Dr. Haley’s influence is observed within the research community as she has been actively engaged for over 19 years. In 2017 she has become the research leader for the Nonlinear Electromagnetic Materials and Processes Research Team within the Photonics Materials Branch where she oversees a team of 10 government employees and 27 on-site contractors including postdocs and students.