Theoretical study for fabricating elliptical subwavelength nanohole arrays by higher-order waveguide-mode interference

• Published in: Results in physics Vol. 14; p. 102460
• Main Authors: Tong, Huan, Xu, Yueqi, Su, Yingwen, Wang, Xiangxian
• Format: Journal Article
• Language: English
• Published: Elsevier 01.09.2019
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2019.102460

A theoretical method is proposed for fabricating elliptical subwavelength nanohole arrays (ESNA) based on the higher-order waveguide mode (WM) interference in an asymmetric metal-cladding dielectric waveguide (AMDW). The finite-element method is used to simulate the optical field distributions in the AMDW. With excitation by 442-nm transverse magnetic (TM) polarized light, the metal layer is a 40-nm-thick silver film and the waveguide layer is a 9650-nm-thick photoresist that can support many guided modes by virtue of its thickness. The interference of TM51 WMs is used to demonstrate the proposed method for fabricating ESNA. The major and minor axes of the nanohole are obtained theoretically as 110 nm and 98 nm, respectively. With a certain photoresist thickness, ESNA with various periods can be fabricated by selecting different guided modes. The proposed method is a simple way to produce ESNA and could have wide applications in the field of nano-optics. Keywords: Elliptical subwavelength nanohole arrays, Lithography, Waveguide mode interference, Asymmetric metal-cladding dielectric waveguide