[7p-A405-1~21] 3.12 Nanoscale optical science and near-field optics

△ [7p-A405-17] Substrate etching technique for shortening of plasmon resonant wavelengths and enhancement of refractive index sensitivity

〇Yuto Moritake¹, Takuo Tanaka^1,2 (1.RIKEN, 2.Tokyo Inst. of Technology)

Keywords:plasmonics, metamaterials

In this study, we propose the substrate etching technique for shortening of plasmon resonant wavelengths and enhancement of refractive index sensitivity. Plasmon resonant wavelengths of metal nanostructures shift to longer wavelengths from their original resonant wavelengths due to refractive index of substrates. Therefore, the size of the nanostructures should be miniaturized for their resonant wavelength to be the designed value, making fabrication more difficult. To solve it, substrate etching technique was introduced. By applying selective etching of Si substrates, the effects of the substrate were reduced, preventing the resonant wavelengths from shifting to longer wavelengths. Moreover, we demonstrated enhancement of refractive index sensitivity by using the substrate etching technique. Since electromagnetic fields under the nanostructures become available by the substrate etching technique, shifts of the plasmon resonant wavelengths due to change in refractive index surrounding the nanostructures get larger.