Aug 5, 2009
Tiny mesh captures near-field behaviour
Researchers in Taiwan have fabricated three different nanosized array structures by electron beam lithography to investigate localized surface plasmons (LSP) – the excitations of electron plasmons bounded in geometries such as bumps or voids.
The trends of the reflectance spectra indicate that the localized surface plasmon modes can be spatially controlled by manipulating geometric parameters, namely the lattice constants of the array. The larger the lattice constants, the lower the frequencies of the LSP modes (note the red shift in the middle of the above image).
To study more of the modulated LSP modes, the researchers meshed the complex domains into simple geometries and applied a finite element method based on the FEMLEB code. Satisfactory agreement between the experimental observations and numerical results was obtained.
The team's array structures were fabricated using well established silicon technology and are reproducible. The implementation of exquisite designs will allow more efficient optical devices to be realized in the future.
The researchers presented their work in Nanotechnology.
About the author
The work was financially supported partially by the National Science Council, Taiwan and was performed in four institutions: (1) Department of Electrophysics, National Chiao Tung University, (2) National Nano Device Laboratories, (3) Research Center for Applied Sciences, Academia Sinica, and (4) Department of Physics, Fu Jen Catholic University. J W Chou, Wen-Chung Fan and Hsun-Chuan Shih are PhD students in the groups of Profs. Der-San Chuu, Wu-Ching Chou and Chih-Wei Luo based at the Department of Electrophysics, National Chiao Tung University. Dr Kao-Chin Lin is a postdoctoral researcher in Prof. Der-San Chuu's Group. Dr Yao-Jen Lee and Fu-Kuo Hsueh are researchers in National Nano Device Laboratories. Dr Chi-Tsu Yuan is a postdoctoral researcher in the Research Center for Applied Sciences, Academia Sinica. Prof. Ming-Chieh Lin has a research group in the Department of Physics, Fu Jen Catholic University. Prof. Chih-Wei, Wu-Ching Chou and Der-San Chuu's research groups are in the Department of Electrophysics, National Chiao Tung University. Prof. Der-San Chuu is the director of the project.