Yuika Saito1, Mitsuhiro Honda1, Koichi Watanabe1, Atsushi Taguchi2, Yujian Song1 and Satoshi Kawata1,2
1Department of Applied Physics, School of Engineering, Osaka University, Suita 565-0871
Light couples with free electrons in metals on the nanometer scale, exhibiting a localization and enhancement effect known as Localized Surface Plasmon Resonance (LSPR). LSPR has been exploited in many scientific and industrial fields, such as sensors, optical waveguides, high-sensitivity optical detection, high-resolution microscopy, etc. In spite of the versatility of LSPR, the applicable wavelength range of LSPR has been limited to the visible and infrared because the host materials for conventional LSPR, mainly gold and silver, do not exhibit metallic behavior at ultraviolet (UV) wavelengths. We used aluminum as a new candidate LSPR material at UV wavelengths and optimized its structure for better coupling with light from UV to deep-UV. Aluminum nanostructures were fabricated by a nanoparticle lithography method. In this report, we especially focus on the relationship between the LSPR wavelength and the height of the nanostructures. By increasing the height of the nanostructures, blue shifts of the LSPR wavelength were observed. With finer tuning of the nanostructures, an LSPR wavelength of 244 nm was successfully achieved, which is the shortest reported LSPR wavelength.
ultraviolet light, plasmonics, aluminum nanostructures, nano sphere lithography
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