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X-WR-CALNAME:Department of Electrical and Computer Engineering (HKUECE) 電機與計算機工程系
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X-WR-CALDESC:Events for Department of Electrical and Computer Engineering (HKUECE) 電機與計算機工程系
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TZID:Asia/Hong_Kong
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TZOFFSETFROM:+0800
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DTSTART:20250101T000000
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DTSTART;TZID=Asia/Hong_Kong:20260331T140000
DTEND;TZID=Asia/Hong_Kong:20260331T150000
DTSTAMP:20260511T035352
CREATED:20260327T023015Z
LAST-MODIFIED:20260327T023015Z
UID:115430-1774965600-1774969200@ece.hku.hk
SUMMARY:RPG Seminar – Broadband Mamyshev Oscillator at 1.7 μm for Multicolor Three-photon Fluorescence Microscopy
DESCRIPTION:Zoom Link:\nhttps://hku.zoom.us/j/95690107722?pwd=KARbsSPDxqYtCaSbRQ0AbxNFmlyBl2.1 \nAbstract\nThree-photon fluorescence (3PF) microscopy enables high-contrast deep-tissue imaging with cellular resolution\, especially in 1.7 μm wavelength range\, yet its widespread adoption has been hindered by the lack of compact\, tunable\, and high-power femtosecond laser sources. Here\, we demonstrate a broadband tunable ultrafast Mamyshev oscillator operating in the 1.7 μm wavelength region\, specifically designed for multicolor 3PF microscopy. The all-fiber ring cavity\, incorporating two arms with tunable grating-based filters\, generates stable ultrashort pulses with flexibly tunable central wavelength from 1730 nm to 1810 nm and adjustable bandwidth up to 140 nm at 10 dB. The oscillator at 7.14-MHz repetition rate are amplified using a chirped pulse amplification (CPA) system to achieve 80-nJ pulses with a slope efficiency of 46.2%\, and finally compressed to 65 fs. We showcase the versatility of this laser source through various imaging modalities. High-contrast\, label-free third-harmonic generation (THG) images of diverse biological samples are presented. Deep-tissue vasculature 3PF images in an ex vivo mouse brain down to a depth of 1 mm are visualized. Crucially\, we achieve multicolor 3PF imaging with a single excitation wavelength for various co-labeled mouse brain samples\, visualizing the interaction between neurons and plaques with distinct morphologies in an Alzheimer’s disease mouse model. This compact\, tunable\, and high-power 1.7 μm ultrafast fiber laser establishes a powerful tool for advanced biomedical imaging\, particularly for deep tissue and multiplexed studies of neurodegenerative diseases. \nSpeaker\nMiss Xiaoxiao Wen\nDepartment of Electrical and Computer Engineering\nThe University of Hong Kong \nBiography of the Speaker\nXiaoxiao Wen received her bachelor’s degree and the master’s degree from the South China University of Technology (SCUT) in 2019 and 2022\, specializing in ultrafast laser dynamics measurement. She is currently a PhD candidate at the Department of Electrical and Electronic Engineering\, the University of Hong Kong\, under the supervision of Prof. Kenneth Kin-Yip Wong. Her current research interests include ultrafast fiber laser\, fiber nonlinearities\, ultrafast measurement\, multiphoton microscopy\, and optical neural networks. \nOrganiser\nProf. Kenneth Kin-Yip Wong \nDepartment of Electrical and Computer Engineering\, The University of Hong Kong \nAll are welcome.
URL:https://ece.hku.hk/events/20260331/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/jpeg:https://ece.hku.hk/wp-content/uploads/2024/11/rpg-seminar.jpg
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