Me @ Medaille

Dr. Sarkar Presents at 2022 American Chemical Society Conference

Assistant Professor of the Practice of Chemistry Dr. Gautam Sarkar attended the spring 2022 American Chemical Society (ACS) national conference in San Diego, California, during March 20-24, presenting his research on polymer-chemistry that was conducted in the summer of 2021.

ABSTRACT: Understanding and controlling light-matter interactions is of central interest for various applications such as communication, renewable energy, and sensing technologies. Photonic crystals (PCs) are a class of materials that can manipulate propagation of electromagnetic waves to on-demand display of different colors, using at least two materials with distinct refractive indices. Briefly, the mechanism of reflection of light in 1-D photonic crystal is driven by following parameters: (1) layer thickness dictates the wavelength of the reflected light according to Bragg’s equation and (2) the difference between the refractive indices dictates the intensity of the reflected light. The goal of this project was to develop two suitable polymers (polystyrene and phenolic resin) and to design their appropriate thicknesses to fabricate a stack of bi-layer films for preparing a photonic crystal that would reflect light in a targeted wavelength range (visible, ~400-700 nm) with desired intensity. Specifically, the layer thickness can be controlled by varying the polymer solution concentrations for spin coating. Additionally, we identified a step of surface treatment is necessary (ozone under UV light and annealing) for improving the wettability between distinct polymer layers.

Publication: “ReflectSim: an open-source software for teaching optical light reflection of nanostructured materials”

Clayton Keene, Mark Robertson, Gautam Sarkar, Jessica King and Zhe Qiang

Abstract: Leveraging computational resources for modern physics education has become increasingly prevalent, especially catalyzed by the COVID-19 pandemic when distance learning is widely implemented. Herein, we report an open-source software for students and instructors to on-demand simulate optical reflection behaviors of one-dimensional photonic crystals (1D-PCs), a model system for understanding light–matter interactions relevant to materials science and optical physics. Specifically, our MATLAB application, ReflectSim, employs an adapted transfer matrix method simulation and can account for the effects of several critical material design parameters, including interfacial roughness and layer geometry, to determine the reflectance spectrum of user-defined 1D-PCs. By packing our codes into a graphical user interface, this software is simple to use and bypass the requirement of any coding experiences from users, which can be widely used as an education tool. We believe that ReflectSim provides great potential for assisting students in understanding optical phenomenon in nanostructured layered materials and relevant scientific concepts through enabling more engaging learning experiences.