Position: PhD Candidate
Current Institution: University of Illinois Urbana-Champaign
Abstract: Emerging Techniques in Infrared Imaging
Infrared (IR) vibrational spectroscopic imaging has emerged as a sophisticated tool for early disease detection and diagnosis providing spectral signatures that are specific to morphology and biochemical properties of cells in tissue. The spectral data measures the molecular content of biological samples optically thereby providing a reagent-free nondestructive tool with wide applications. However crucial barriers to achieving this goal are (1) long acquisition times (2) limited spatial details and (3) limited understanding of the theory of light-matter interactions. Building upon the recent advances in quantum cascade lasers (QCLs) I have addressed these three limiting challenges in IR imaging by combining innovative techniques in hardware development and software design. As with standard microscopy techniques the optical configuration plays a critical role in optimizing the speed of the system. We have developed the first instance of a laser scanning microscope that demonstrates a ten-fold improvement in speed. With this technique label-free classification of surgical tissue sections is accomplished within minutes as opposed to hours with state-of-the-art designs. The applicability of the developed instrument spans beyond measuring molecular contrast. It demonstrates polarization IR imaging and the first instance of imaging site-specific chirality of molecules within a fraction of a minute. The developed paradigm can elucidate the secondary structures in a sub-microliter sample volume of biomolecules such as proteins and amino acids. Next using a decision theory framework we demonstrate that a combination of spatial and spectral information heralds an improved classification performance. We also utilize a similar rationale of likelihood approach to show an improved performance in the detection limits of an IR instrument. The demonstrated ability to detect minute quantities of biomolecules is of crucial interest to a wide variety of applications including forensic studies regulatory monitoring and contaminant residue detection.
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 a M.S. from California Institute of Technology (Caltech) both in Electrical Engineering. After working as an analog research engineer with Finisar and Swedish Institute of Space Physics she joined Prof. BhargavaÂ’s research group to develop next-generation IR imaging instruments. Using her expertise in spectroscopic imaging for remote sensing applications she now seeks to develop novel cancer imaging technology. Yamuna is a recipient of prestigious President of India Award (IIT-R) Jet Propulsion Laboratory (JPL) Fellowship (Caltech) Nadine Barrie Smith Award and James Henderson Fellowship (UIUC). She is a passionate teacher and has been recognized by the Harold Olsen Award (UIUC) for undergraduate teaching. She currently serves as President of the Society of Photo-Optical Instrumentation Engineers (SPIE) student chapter at UIUC.