Electronic Engineering Department, The Chinese University of Hong Kong - Recent Achievements from Solid State Electronics and Photonics Group


Recent Achievements from Solid State Electronics and Photonics Group

Silicon Photonics and Nanophotonic devices
In 2008 Prof Tsang received funding from the University Grants Council totalling just over HK$10 million to purchase an electron-beam lithography system that can be used to make nanophotonic devices with feature sizes as small as 10nm. In 2006, he received $6.5 million funding for an ICP dry etching system. Prof. H.K Tsang was awarded the Research Excellence Award 2006-2007 of CUHK, in recognition of his contributions in nonlinear silicon photonics, particularly the first measurements of nonlinearities in silicon waveguides at telecom wavelengths and on the understanding of the role of free carrier absorption in silicon Raman amplifiers. One of his students, Dr. T. K. Liang, was awarded the Young Scientist Award by the Hong Kong Institution of Science (HKIS) (2005) for his 2004 work, while he was a PhD student in Prof Tsang’s group, in showing experimentally that silicon optical waveguides can provide over six times gain in amplifying optical pulses using Stimulated Raman scattering.

Advanced Optical Processing for Next Generation Fiber Communications
Prof. Shu Chester’s team has demonstrated significant research progress in the area of optical communications as reflected by a number of research awards and paper awards. His Ph.D graduate, Fok Mei Po Mable, received the IEEE Hong Kong Section Postgraduate Paper First Prize in 2007, and the CUHK Best Research Output Award by research postgraduate student in the same year, based on the work in optical processing for advanced fiber-optic communication systems. She also obtained the prestigious IEEE LEOS Graduate Student Fellowship Award in 2005. Prof. Shu’s another Ph.D graduate Dr. Chow Kin-Kee received the Young Scientist Award from the Hong Kong Institution of Science (HKIS) in 2004 for his work on optical processing with nonlinear photonic crystal fiber. Other students in his team received best paper awards from many academic conferences including the Conference on Lasers and Electro-Optics/Pacific Rim, Asia Optical Fiber Communication Conference, and the IEEE LEOS (HK) Postgraduate Conference, all in the areas of optical fiber communications.

A significant citation of a pioneering paper by an EE team
One of early Applied Physics Letter papers by an EE team on semiconductor surface morphology by AFM (C. C. Hsu, Y. C. Lu, J. B. Xu, I. Wilson, Appl. Phys. Lett. 64, 1959 (1994).) has been cited by a Science paper (2006) from an IBM research group on silicon. The journal is very prestigious in science and technology community. The EE's team work has drawn global attention after its publication. Since then AFM has been widely used for surface quality test in various sectors of information technology industry.

Biophotonics--Femtosecond fusion
Prof. Chan KT and his student, Mr. He Hao, published a recent paper on Biophotonics in Applied Physics Letters Vol.93, 163901 (2008). This paper has been highlighted in the 2008 Dec. issue of a very prestigious journal, Nature Photonics. The quotes from Nature Photonics read:
Researchers in Hong Kong have come up with a way of efficiently fusing human cells together using femtosecond light pulses from a fibre laser. Cell fusion happens naturally, but the ability to do it artificially provides cell biologists with a better understanding of the process. This in turn could lead to developments in genetic techniques and cancer treatments. Previous optics-based fusion techniques, such as the use of nanosecond-long pulses of UV light, have suffered from poor fusion success rates, about 10%, and surrounding cells were damaged by scattered light. Polyethylene glycol was found to improve the efficiency for fusing yeast cells, but it is toxic. The challenge is to improve the efficiency, but at the same time keep the cells alive. Hao He and co-workers from the Chinese University of Hong Kong take an all-optical approach that does not require any chemicals. Optical tweezers moved two human heptocellular carcinoma cells (HepG2) into contact. Pulses of light 200 fs long, at a wavelength of 1,550 nm were focused onto the contact area for about 10 s. The cells were then incubated for 90 minutes at 37 °C. The fusion was successful in 37.5% of the tests. Thermal effects were limited to the focal volume, reducing disruption to surrounding cells. The technique was also used to join two different types of cell, HepG2 and human cervical cancer cells, although this was achieved at a much lower efficiency of 10%.