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Ptychography has emerged as a transformative coherent diffraction imaging technique for both fundamental and applied sciences. In this talk, I will discuss our new developments in ptychography for lensless bio-imaging, focusing on microscopy and endoscopy applications. In the coded ptychographic microscopy platform, we translate the samples across the disorder-engineered surfaces for lensless diffraction data acquisition. The entire system can be built using a modified Blu-ray player with its 405 nm laser from the optical pickup head. With this platform, we report the direct observation of bacterial growth in a 15-s interval at a centimeter-scale area, with a phase sensitivity like that obtained from interferometric measurements. This enables precise cell growth characterization, rapid bacterial detection, and antibiotic susceptibility testing at the single-cell level. The imaging throughput is orders of magnitude higher than that of conventional microscope. In the ptychographic endoscopy platform, we use a handheld, lensless fiber bundle to synthesize large virtual apertures, resolving features down to 548 nm with an extended depth of field exceeding 2 cm. This allows high-resolution imaging of complex biological surfaces. Our approaches uniquely combine high phase sensitivity, high spatiotemporal resolution, and ultra-large field of view, opening new possibilities in biomedical research and clinical diagnostics across microscopic and endoscopic domains.
Dr. Guoan Zheng is currently the UTC Associate Professor at the University of Connecticut (UConn). He also serves as the Director of the newly established UConn Center for Biomedical and Bioengineering Innovation (CBBI). His research focuses on developing novel imaging and sensing tools to tackle complex measurement challenges in biology, medicine, and metrology. Dr. Zheng received his B.S. from Zhejiang University in 2007 and his Ph.D. in Electrical Engineering from Caltech in 2013, where he was awarded the Caltech Demetriades Thesis Prize. Dr. Zheng is recognized for his pioneering work on Fourier ptychography, which has been adopted worldwide and become a standard tool in microscopy imaging. This technique is also featured as a chapter in Joseph Goodman’s classic textbook “Introduction to Fourier Optics (4th edition)”. Dr. Zheng's research has been cited over 12,000 times, with an h-index of 58, and he has been consistently listed as World’s Top 2% Scientists released by Stanford University.