Abstract: Often referred to as the molecular fingerprint region, the mid-infrared (mid-IR) region of the electromagnetic spectrum 2–20 μm has long attracted scientific and technological interest. Specifically, mid-IR microscopy seeks to measure the molecular content of biological samples by probing fundamental vibrational modes, thereby providing a reagent-free, nondestructive tool with wide applications such as early disease detection and diagnosis. However, some barriers in this emerging field are the long acquisition times, limited spatial detail, and limited understanding of light-matter interactions. Moreover, efficient techniques that map the molecular and structural organization, still remain sparse. In this research talk, I will focus on advanced mid-IR spectroscopic imaging platforms that help address these three major classes of challenges. Using a decision theory framework, an improved perceived spatial resolution limit is demonstrated through a combination of spatial and spectral information. Optimal design of IR microscopes facilitates label-free classification of surgical tissue sections within minutes as opposed to hours with state-of-the-art objective or stage scanning designs. The applicability of the developed rapid design spans beyond measuring molecular contrast to enable polarized measurements of the biomolecules and polymers. These developments allowed the first instance for imaging site-specific chirality of molecules within a fraction of a minute, orders of magnitude faster than traditional bulk measurements. Specific challenges associated with engineering chirality mapping platforms and roadblocks to a viable and accurate system will also be discussed. Together, these results emphasize the approach of using theory and modeling-guided development of measurement technology to open new opportunities in understanding biomolecules.
Bio: Yamuna Phal is a Ph.D. candidate in Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign (UIUC). She received her B.Tech. from Indian Institute of Technology Roorkee (IIT-R) and an M.S. from California Institute of Technology (Caltech), both in Electrical Engineering. After working as an analog research engineer with Finisar and the Swedish Institute of Space Physics she joined Prof. Rohit Bhargava’s research group to develop next-generation IR imaging instruments. Yamuna’s recent publications include the invention of VCD imaging (Analytical Chemistry, 2021) and using decision theory to provide an analytical formulation for the resolution limit for spectral imaging systems (Journal of Physical Chemistry C). Both of these studies were featured on the respective journal covers, blending Yamuna’s interest in science and art. Her work has been recognized by awards in several scientific communities, including the best student poster awards at FACSS SciX 2021 and Chirality Yamuna is a recipient of the prestigious Cadence Women in Technology Program, President of India Award (IIT-R), and Jet Propulsion Laboratory (JPL) Fellowship (Caltech). She is a passionate teacher and mentor, for which she is grateful to be recognized by the Harold Olsen Award and E. A. Reid Fellowship for undergraduate teaching and engineering education at UIUC. She has also been nominated to the list of teachers rated excellent while four of her mentored teams have