The manipulation of micron-sized particle by light
I research on the theory of optical micromanipulation – how optical force (light)
can move and confine small micron-sized particles. The significance of optical forces
can be seen in a “back-of-envelope” calculation: by focusing a 0.1W laser to a micron-sized
particle and assuming modest momentum absorption of ~10%, the resultant acceleration can reach .
This “astronomical” acceleration implies a great potential. Indeed, this technique is having major
impacts on many important fields (e.g. Physics, Chemistry, Biology, engineering etc.)
that involve small particles.
Metamaterials and Transformation Optics
Transformation optics is a powerful method to design novel electromagnetic devices. For example,
people have applied transformation optics to demonstrate theoretically the possibility of achieving
invisibility and optical illusion. However, in order to build these devices, one needs materials with
very special electromagnetic properties, which may not be available in nature. This is the reason why
one needs metamaterials, which are man made materials that are designed to give a wide range of optical properties.
Jun Chen, Jack Ng (corresponding author), Zhifang Lin, and C. T. Chan, “Optical pulling force ”, Nature Photonics 5, 531 (2011).
Shubo Wang, Jack Ng, Hui Liu, Huiho Zheng, Zhihong Hang, and C. T. Chan “Sizable electromagnetic forces in parallel-plate
metallic cavity”, Phys. Rev. B 84, 075114 (2011).
Hui Liu, Jack Ng, Shubo Wang, Zhifang Lin, Zhihong Hang, C. T. Chan, and Shining Zhu, “Strong light-induced negative optical
pressure arising from kinetic energy of conduction electrons in plasmon-type cavities”, Phys. Rev. Lett. 106, 087401 (2011).
Joseph Junio, Jack Ng, Joel A. Cohen, Zhifang Lin, and H. Daniel Ou-Yang, “Ensemble method to measure the potential energy
of nanoparticles in an optical trap”, Opt. Lett. 36, 1497 (2011).
Jack Ng, Zhifang Lin, and C, T, Chan, “Theory of optical trapping by an optical vortex beam”,Phys. Rev. Lett. 104, 103601 (2010).[
Yun Lai, Jack Ng, HuanYang Chen, DeZhuan Han, JunJun Xiao, Zhao-Qing Zhang, and C. T. Chan, “Illusion optics: The optical
transformation of an object into another object ”, Phys. Rev. Lett. 102, 253902 (2009).
Jack Ng, Huanyang Chen, and C. T. Chan, “Metamaterial frequency-selective superabsorber”, Opt. Lett. 34, 644 (2009).
Jack Ng and C. T. Chan, “Size-selective optical forces for microspheres using evanescent wave excitation of whispering
gallery modes”, Appl. Phys. Lett. 92, 251109 (2008).
Jack Ng, Ross Tang, and C. T. Chan, “Electrodynamics study of plasmonic bonding and antibonding forces in a bisphere”, Phys. Rev. B 77, 195407 (2008).
Jack Ng and C. T. Chan, “Localized vibrational modes in optically bound structures”, Opt. Lett. 31, 2583 (2006).
Jack Ng, C. T. Chan, Ping Sheng, and Zhifang Lin, “Strong optical forces induced by morphology dependent resonance”, Opt. Lett.30, 1956 (2005).
Jack Ng, Zhifang Lin, C. T. Chan, and Ping Sheng, “Photonic clusters formed by dielectric microspheres: Numerical simulations”, Phys. Rev. B 72, 085130 (2005).