My major interest in physics is the electromagnetic theory, especially optics. Start form year 1 of bachelor course, I joined the independent research course under Prof. K.K.Fung for studying the structural color form nature, like the scales of butterflies, bees and seashells. The structural color surprised me a lot and imprinted in my brain, because the simplicity and complexity about it. The basics theory is simple, just because of thin film reflection or interference; while the way of expression or the range of application can be in thousand combinations. If the thickness of the rods-like or planar structures changes a little, the color changed a lot! This can be applied to display technology. During the course, I used SEM, TEM for sample cutting, preparation and examination.
After that 1 year independent research course, I exchanged to the National University of Singapore. In there, I picked optic course, which is not taught in Hong Kong. That course brings me into the theory of electromagnetism. I realized that the 4 Maxwell’s Equations are so important and elegant. When I backed to Hong Kong, I chose a rather difficult course for year 2 students, the EM2, which is from solving the Maxwell’s equations to Special Relativity. At the end of the course, some fundamental problems, like electron’s size and self-energy was taught and inspired me a lot. For example, Maxwell’s equations are just a good approximation under classical condition.
On Year 3, the final year, I took a final year project in experiment. I choose to do experiment rather than study theory is because I believe only the nature can tell you the truth, not theory. By polishing my experimental skill and technique, I wish I could read data, graphs and results in correct way. After study electromagnetism and optics for the past 2 years, I found that the structural color belong to a larger sector, photonic crystal. Thus, I joined Prof. W.Y. Tam’s research group on photonic crystal fabrication. At that time, I follow a Master course student, being her assistant in her research. The objectives are fabrication of micro-sized gold particle array and study the transmission or reflection enhancement due to the surface plasmon. The holographic lithography is the mean for the fabrication. We used expanded laser beam for creating large size uniform grid and sputtered the grid with gold to form gold particle array. The optical spectrum measurement conduced from IR to UV. For the IR range, we used FTIR technique. Through out the project, I realized that metallic structures are very interesting because of the large induced current and magnetic field by shinning light on it. At that time, a negative refractive index metameterial for microwave was successfully produced and reported on Scientific American. Therefore, I proposed to Prof. W.Y.Tam for fabrication of the similar structures by holographic lithography as my research objective for the master’s course.
