简介: |
1. Title: Ultrafast laser applications in parallel laser fabrication and multi-photon imaging
Shih-Chi Chen, Ph.D.
Assistant Professor, Department of Mechanical and Automation Engineering
The Chinese University of Hong Kong
Abstract:
I will present our recent work on femtosecond laser manipulation based on digital micromirror devices (DMD) and binary hologram; and its applications in developing the next-generation two-photon excitation microscopes as well as parallel laser fabrication systems. The DMD-based pulse/beam shaper can arbitrarily shape a femtosecond laser at a speed of up to 30 MHz and 32 kHz respectively, around 3 orders of magnitude faster than any existing methods. The DMD beam shaper is integrated with a custom-built laser scanning two-photon microscope to realize new imaging functions including multi-depth imaging, arbitrary surface imaging, and random-access scanning for real-time in vivo biological studies. In the second part, I will present a temporal focusing-based laser fabrication system, where the spectrum of the femtosecond laser pulse is first spatially separated by a DMD, serving simultaneously as a diffraction grating and a programmable binary mask. After collimation, an objective lens recombines the spectrum to the focal region, forming a high-intensity, depth resolved light sheet for laser micromachining, two-photon polymerization and multi-photon imaging. The seminar will be concluded with future research directions.
Biographical Sketch:
Dr. Shih-Chi Chen received his B.S. degree in Mechanical Engineering from the National Tsing Hua University, Taiwan, in 1999. He received his S.M. and Ph.D. degrees in Mechanical Engineering from the Massachusetts Institute of Technology, Cambridge, in 2003 and 2007, respectively. Following his graduate work, he entered a post-doctoral fellowship in the Wellman Center for Photomedicine, Harvard Medical School, where his research focused on biomedical optics and endomicroscopy. From 2009 to 2011, he was a Senior Scientist at Nano Terra, Inc., a start-up company founded by Prof. George Whitesides at Harvard University, to develop precision instruments for novel nanofabrication processes. In 2011, he joined the Department of Mechanical and Automation Engineering at the Chinese University of Hong Kong (CUHK) as an Assistant Professor. His current research interests include ultrafast laser applications, biomedical optics, precision engineering, and nanomanufacturing. Prof. Chen is a member of the American Society for Precision Engineering (ASPE), ASME, SPIE, OSA, and IEEE. He is the recipient of a 2003 R&D 100 Award for the design of a microscale six-axis nanopositioner. In 2013, he received the Early Career Award from University Grants Committee of Hong Kong.
2. Title: Unobtrusive Smart Sensing Technologies for mHealth
Ni Zhao, Ph.D.
Associate Professor, Department of Electronic Engineering
The Chinese University of Hong Kong
Abstract:
With the growing aging population and prevalence of cardiovascular diseases, there is an increasing demand for developing personal healthcare systems that can frequently collect physiological parameters of patients during their daily life, thus allowing early disease detection and timely response of health treatments. Wearable medical electronics have been proposed owing to their capability of continuously monitoring the physiological conditions of individuals outside hospitals.
In this talk I will present the emerging nanotechnologies and machine learning methods that enable a new generation of intelligent health monitoring devices. In the first part, I will talk about the design and fabrication of flexible mechanical and optical sensors for high accuracy measurement of blood pressure, a key bio-marker for cardiovascular systems. The mechanical piezoresistive sensor features a 3D hollow graphene structure embedded in a silicone material, allowing decoupled tuning of sensor sensitivity and mechanical flexibility. The optical sensor exploits a hybrid inorganic LED - organic phototransistor sensing scheme to enable high energy efficiency photoplethysmogram signal monitoring. In the second part, I will introduce how machine learning methods can help us to better utilize the sensor signals to track the variation of human physiological status.
Biographical Sketch:
Ni Zhao received her Ph.D degree in Physics from the University of Cambridge (UK) in 2008. From 2008-2010 she worked as a postdoctoral research fellow at the Massachusetts Institute of Technology (USA). Her work at MIT involved developing novel hybrid solar cell structures that incorporate colloidal nanocrystal quantum dots with organic and inorganic materials, and using these structures to study electronic processes in solar cells. Prior to MIT she worked in the Optoelectronic Group at the Cavendish Laboratory in Cambridge, UK. Her PhD dissertation was focused on device physics of polymer based field-effect transistors, charge transport mechanism at organic semiconductor/ dielectric interface and nanoscale patterning using inkjet-printing technique. During her M.S Degree, Zhao worked in the Xerox Research Center of Canada on novel semiconducting polymers and their applications in field-effect transistors.
Ni Zhao joined the Department of Electronic Engineering at the Chinese University of Hong Kong (CUHK) in December 2010. |
