MS Thesis Defense by Vidhi Singla
Virtual
Heather Blaser
7742652040
hblaser@umassd.edu
https://umassd.zoom.us/j/91017390345?pwd=gAgrVmNcwf0aeGTwbjVTtTskMjJVlP.1
Title: Single-Particle Chiral Spectromicroscopy:Artifact Correction and Characterization of Plasmonic Nanostructures by Vidhi Singla
Advisor: Dr. Wei-Shun Chang, Chemistry & Biochemistry Dept.
Committee Members: Dr. Catherine Neto, Chemistry & Biochemistry Dept. & Dr. Milana Vasudev, Bioengineering Dept.
Abstract:
Chirality plays a critical role in biology and medicine, yet conventional techniques such as optical rotatory dispersion and circular dichroism suffer from low detection sensitivity. Plasmonic nanostructures enhance chirality detection through localized surface plasmon resonance, but their inherent size and shape heterogeneity makes single-particle measurements essential. Existing single-particle dark-field scattering methods, however, suffer from linear dichroism artifacts caused by imperfect waveplate retardance, resulting in ±10% measurement uncertainty.
This thesis develops an artifact-free single-particle chiral dark-field scattering spectromicroscopy. Using unpolarized excitation and a quarter-wave plate/Wollaston prism detection assembly, left- and right-handed circularly polarized scattering are simultaneously decoded. Dual measurements at ±45° waveplate orientations eliminate linear dichroism artifacts while preserving true chiral signals, verified by Stokes–Mueller calculus. The method enables accurate, high-throughput chirality characterization without modifying existing instrumentation.