Major research activity
We investigate novel phenomena and applications induced by femtosecond (fs) laser. Compared to continuous wave laser, fs laser has several characteristics such as tunable wavelength, high peak power, and much shorter pulse duration. Accordingly, fs laser is considered as a promising light source for spatiotemporal investigations. In recent years, fs laser trapping has received much attention because of its remarkable efficiency to gather nanoparticles toward the laser focal spot. In order to clarify the mechanism, our approach is to study dynamics of single particles under fs laser trapping. It was found that dynamics of a target particle is actually size-, laser mode-, and laser power-dependent. These findings provide us a deeper understanding for optical manipulation of nanoparticles.
On the other hand, we are also interested in light-induced nucleation of biomolecules from their supersaturated solutions. After systematic investigation, we found glycine crystallization can be greatly accelerated by focusing the laser beam at the air/solution interface. Later we further extended crystallization to amyloid fibril formation as it is considered that aggregation and nucleation can be assisted under fs laser irradiation by locally generating cavitation bubbles in supersaturated solutions. In the future, we would like to put more effort into laser manipulation and fabrication.
Major relevant publications
- T.-H. Liu, T. Uwada, T. Sugiyama, A. Usman, Y. Hosokawa, H. Masuhara, T.-W. Chiang, and C.-J. Chen, Single Femtosecond Laser Pulse-Single Crystal Formation of Glycine at the Solution Surface, J. of Cryst. Growth, 366, 101-106 (2013)
- T.-H. Liu, W.-Y. Chiang, A. Usman, and H. Masuhara, Optical Trapping Dynamics of a Single Polystyrene Sphere: Continuous Wave versus Femtosecond Lasers, J. Phys. Chem. C, 120, 2392–2399 (2016)
- T. Uwada, S.-F. Wang, T.-H. Liu, and H. Masuhara, Preparation and Micropatterning of Gold Nanoparticles by Femtosecond Laser-Induced Optical Breakdown, J. Photochem. Photobiol. A, 346, 177-186 (2017)
- T-H. Liu, K. Yuyama, T. Hiramatsu, N. Yamamoto, E. Chatani, H. Miyasaka, T. Sugiyama, and H. Masuhara, Femtosecond-Laser-Enhanced Amyloid Fibril Formation of Insulin, Langmuir, 33, 8311-8318 (2017)