Takashima, Yuusuke Tokushima University Tokushima University Educator and Researcher Directory
Kusaba, Keita Tokushima University
Haraguchi, Masanobu Tokushima University Tokushima University Educator and Researcher Directory KAKEN Search Researchers
Naoi, Yoshiki Tokushima University Tokushima University Educator and Researcher Directory KAKEN Search Researchers
Refractive index sensor
A highly sensitive refractive index sensor with normally incident optical geometry was experimentally demonstrated using dual resonance in a subwavelength grating (SWG) on a waveguide. Two eignemodes within the SWG and waveguide were utilized for refractive index sensing with the reduction of noise such as background noise. The finite-difference time-domain numerical method was used to estimate the refractive index sensing performance of our sensor. The calculated electric field clarified that the incident light could excite modes in the SWG and waveguide with normally incident optical geometry, and the modes formed two resonance reflection peaks. The calculation showed that these dual resonance peaks depended differently on the refractive index of the ambient around the sensor, and the intensity difference between both resonance peaks varied with the slight change in refractive index of the ambient. The sensor was fabricated using traditional electron-beam lithography techniques, and two reflection resonant peaks were experimentally obtained. The difference between the dual resonance peak intensities varied significantly with the minuscule change in refractive index of the ambient around the sensor, and the resolution of the refractive index reached 7.65 × 10–4, assuming a spectrometer intensity sensitivity of 1%.
IEEE Sensors Journal
© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
|DOI (Published Version)|
|URL ( Publisher's Version )|
ieeesens_19_15_6147.pdf 1010 KB
Science and Technology