(A) study about fabrication and arrangement of silver nanostructures by femtosecond laser

Abstract

The conventional bottom-up nanofabrication has a problem in that it is difficult to form well-arranged nano pattern on a substrate and the degree of freedom of shape control is low. However, the optical nanofabrication using light has possibility to enable unique shape control that does not exist in nature and to be applied to the production of new optical device. In this research, we have studied about the fabrication of various shapes of silver nanostructures and the direction of alignment by controlling the wavelength and polarization state of the femtosecond laser beam. By controlling the polarization state of the laser, the direction of the silver nano plate can be freely controlled and the aspect ratio of the silver nano plate can be controlled by controlling the wavelength of the laser. In addition, FDTD simulation was performed to explain the growth principle of silver nanostructure, and it was confirmed that the electric field intensity localized on the gold seed is one of the factors that greatly influences the control of the shape of the silver nanostructure. This research is expected to be applied to future sensing platforms, metamaterials and photonic crystals.