Note: this event includes two 30-minutes talks given by two UR students. See below for titles, abstract and bios of the two talks.
Combining AI with Polarization: Enhanced Detection and Modeling for Healthcare Applications
Bereket Temesgen, University of Rochester
Abstract
Skin cancer is the most common cancer worldwide, underscoring the need for accessible and efficient diagnostic tools. Polarimetric imaging, which assesses light polarization and how it changes, has shown significant promise for identifying early-stage skin cancer. Our device, Aurora, introduces a compact monocular camera built with a single-layer metalens, leveraging advanced metaoptics similar to those integrated in recently released Android smartphones. Aurora’s design eliminates the need for bulky optical components, time-domain multiplexing, and active laser illumination, capturing precise 4D imaging data—including all-in-focus 2D intensity, depth, and polarization—critical for comprehensive diagnosis. Notably, the device captures these data in a single snapshot rather than the typical 4 to 16 images, providing a more streamlined solution that weighs less than an iPhone.
Aurora’s analysis focuses on the degree of polarization along with other essential optical factors, capturing high-quality polarimetric data that can be represented as a 4x1 Stokes or 4x4 Mueller matrix. This data format is compatible with AI-driven diagnostic models; for example, our random forest algorithm achieved a 91% accuracy in classifying Melanoma phantoms, the deadliest form of skin cancer. Furthermore, Aurora incorporates AI-driven metasurface design, allowing the creation of metalenses optimized for various substrates.
About the speaker
Bereket Temesgen, born in Ethiopia and now living in Boston, is a first-generation sophomore undergraduate studying optical engineering and computer science at the University of Rochester. Bereket’s work on cancer diagnostic tools stems directly from the challenges they observed in Ethiopia's healthcare infrastructure, where access to advanced diagnostic technology is limited. Driven by a passion to bridge this gap, Bereket’s project recently earned recognition at a Medtronic-hosted competition, highlighting the potential impact of polarimetric imaging on early-stage cancer detection.
In addition to academic pursuits, Bereket enjoys producing and recording music. He’s collaborated with local bands, including Uma Thermos and Enfierce, and otherwise serves as the lead engineer for Rochester Producers and Musicians, a student organization.
Understanding the Interplay of Thermal and Laser Intensity Effects on Plasmonic Photocatalysis Using Upconverting Nanoparticle Thermometry
Laura Signor, University of Rochester
Abstract
Numerous experimental studies have demonstrated that chemical reaction rates can be significantly increased with plasmonic photocatalysis. However, the relative contribution of hot electron versus thermal effects to the observed enhancement is still debated. Operando thermometry techniques can play a critical role in elucidating the physical mechanisms behind plasmonic photocatalysis if high-fidelity thermometers with the requisite chemical inertness, thermal stability, and spatial resolution can be identified. Our previous work demonstrated that a single near-infrared (808 nm) laser can simultaneously excite NaYF4:Nd3+,Yb3+,Er3+ upconverting nanoparticles (UCNPs) that serve as luminescent thermometers and photocatalyze the dimerization of 4-nitrothiophenol (4-NTP) to 4,4’-dimercaptoaazobenze (DMAB) utilizing silver-coated silicon nanopillars as the plasmonic substrate. We measured an increase in the surface temperature that was correlated with the reaction progress, but because this laser induced temperature rise is inherently coupled with the laser intensity, disentangling laser intensity and heating effects is very difficult. To determine if heating is an integral component of the photocatalysis process, we will keep the plasmonic structure optically the same while changing its heat dissipation properties, by maintaining a constant laser intensity while changing only the laser induced temperature rise in a controlled manner by altering the substrate's thermal conductivity. Comparing the chemical reaction on otherwise identical plasmonic samples with different substrate thermal conductivities allows us to investigate the role of laser heating independently from laser intensity.
About the speaker
Laura Signor is a PhD student at the Institute of Optics at the University of Rochester, where she conducts research on nanoscale heat transfer focusing on plasmonic photocatalysis in the lab of Dr. Andrea Pickel. Prior to her graduate studies, Laura gained valuable industry experience working at Corning in Fairport, specializing in thin film coatings. She holds a master’s degree in Environmental Engineering from the University at Buffalo and a bachelor’s degree in Mathematics and Physics from SUNY Geneseo. Outside of academia, Laura enjoys painting, running, and spending quality time with her cat.
Parking and location
The talk will be held at UR River Campus, Goergen 101. Parking is available in the lot across the street in Intercampus Drive Lot, and is free for talk attendees (no pass needed).
Pre-talk dinner
A pre-talk dinner will be held at 5:15 pm at the King and I Thailand Cuisine located at 1455 East Henrietta Rd, Rochester, NY 14623. If you would like to attend, please contact the house committee by email to make reservations. Email: house@opticarochester.org
