Authentication labels based on guided-mode resonant filters |
| |
Authors: | Wu Mount-Learn Hsu Che-Lung Lan Hsiao-Chin Huang Hung-I Liu Yung-Chih Tu Zong-Ru Lee Chien-Chieh Lin Jian-Shian Su Chih-Chieh Chang Jenq-Yang |
| |
Affiliation: | Department of Optics and Photonics, National Central University, Jhongli, Taiwan. mlwu@dop.ncu.edu.tw |
| |
Abstract: | A guided-mode resonance (GMR) filter with wide angular tolerances is experimentally demonstrated as an authentication label illuminated with unpolarized white light. The proposed filter, based on a free-standing silicon nitride membrane suspended on a silicon substrate, is fabricated by using anisotropic wet etching to remove the substrate beneath the silicon nitride layer. Both grating and waveguide structures without a lower cladding layer, i.e., a substrate, are fabricated simultaneously on a silicon nitride membrane. Since the silicon nitride is transparent within the spectra of visible and infrared light, such suspended-membrane-type GMR filters are well suited for applications within the visible spectrum. Moreover, the high refractive index of silicon nitride allows the proposed filters to have strongly modulated gratings and an immunity to high angular deviation. The measured reflection resonance has an angular tolerance up to +/-5 degrees under normal incidence for the wavelength of 629.5 nm. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|