[16p-P10-1~9] 3.1 Basic optics and frontier of optics

▲ [16p-P10-6] Optical trapping-formed colloidal assembly with light propagation studied by transmission spectral and diffraction pattern measurements

〇(M1)Ching-Hsiang Tseng¹, Tetsuhiro Kudo¹, Shun-Fa Wang¹, Ken-ichi Yuyama², Hiroshi Masuhara¹ (1.National Chiao Tung Univ. Taiwan, 2.Research Inst. for Electronic Science, Hokkaido Univ.)

Keywords:optical trapping, colloidal assembly, transmission spectra measurement

Upon focusing intense laser beam into solution, small particles receive optical force and are trapped in the potential well, forming an assembly inside the irradiation area. In our previous work, we focused a 1064 nm laser on the glass/solution interface and trapped diffusing polystyrene nanoparticles of 500 nm in diameter. The trapping results in formation of a single assembly which is larger than the irradiation area. Further we found that linearly aligned particles showing horn-like structures expand out from the assembly. We proposed that this horn extension is due to light propagation of the trapping laser through the periodic assembly structure.
In order to elucidate the assembling structure and its forming dynamics, we studied this phenomenon by transmission spectral and diffraction pattern measurements. It is worth noting that the assembly structure with and without horn are different from each other.