Nov 4 (Tue) @ 10:00am: "High-Speed CMOS SPAD Imager for Fluorescence Lifetime Imaging Microscopy," Macan Tadayon, ECE PhD Defense

Location: Engineering Science Bldg (ESB), Room 1001
Zoom Meeting: https://ucsb.zoom.us/j/89630097245?pwd=Uu2yyb8JWAyG82aZgwbO9maTfwrZl9.1
Research Area: Electronics & Photonics
Research Keywords: Circuit Design, Biomedical Imaging

Abstract

Fluorescence Lifetime Imaging Microscopy (FLIM) is a versatile technique for characterizing the biochemical and biophysical properties of living systems. Unlike conventional fluorescence imaging methods that rely on signal intensity, FLIM measures the fluorescence decay time of emitted photons. Since this parameter is largely independent of fluorophore concentration and instead reflects the local chemical environment, it enables quantitative analysis of molecular interactions, pH variations, and energy transfer processes within biological samples.

This work presents the design and characterization of a high-speed CMOS image sensor employing single-photon avalanche diodes (SPADs) for time-resolved fluorescence lifetime measurements. The proposed architecture integrates fast photon detection, precise timing circuits, and optimized readout electronics to achieve high temporal resolution and low noise. A comparative analysis with existing sensor technologies highlights the trade-offs between speed, sensitivity, and scalability, demonstrating the advantages of the proposed system.

Experimental validation was conducted using carboxyfluorescein solutions across a range of pH levels. The imager successfully captured distinct lifetime variations corresponding to environmental changes, confirming its capability for accurate and quantitative fluorescence lifetime measurement. These results establish the system’s potential for a wide range of biomedical and biochemical imaging applications, with future improvements aimed at increasing sensitivity, measurement precision, and imaging throughput.

Bio

Macan Tadayon is a Ph.D. candidate in Electrical and Computer Engineering at the University of California, Santa Barbara, advised by Professor Luke Theogarajan. His research focuses on the design and development of high-speed CMOS SPAD imagers for Fluorescence Lifetime Imaging Microscopy (FLIM). His work aims to advance quantitative fluorescence imaging for biomedical and life science applications.

Before pursuing his doctorate, he earned both his Bachelor of Science (2015) and Master of Science (2017) degrees in Electrical Engineering from the University of California, Los Angeles. Between 2015 and 2017, he conducted research on neuromorphic circuits, developing neurologically inspired systems that enable signal-parallel processing, real-time pattern recognition, and adaptive learning.

Since 2017, Macan has worked in the semiconductor industry as an RF and analog integrated circuit designer at several leading companies, including Broadcom, Qualcomm, and, most recently, Intel. His professional experience complements his academic research in the design of mixed-signal and imaging systems.

Hosted By: Professor Luke Theogarajan

Submitted By: Macan Tadayon <macan_tadayon@ucsb.edu>