A multichannel color filter with the functions of optical sensor and switch

• Published in: Scientific reports Vol. 11; no. 1; p. 22910
• Main Authors: Chou Chau, Yuan-Fong, Chou Chao, Chung-Ting, Huang, Hung Ji, Chen, Sy-Hann, Kao, Tsung Sheng, Chiang, Hai-Pang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25-11-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624; 639/925; Cavities; Color; Electromagnetic fields; Finite element method; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary); Sensors
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-02453-2

This paper reports a multichannel color filter with the functions of optical sensor and switch. The proposed structure comprises a metal–insulator–metal (MIM) bus waveguide side-couples to six circular cavities with different sizes for filtering ultra-violet and visible lights into individual colors in the wavelength range of 350–700 nm. We used the finite element method to analyze the electromagnetic field distributions and transmittance properties by varying the structural parameters in detail. The designed plasmonic filter takes advantage of filtering out different colors since the light-matter resonance and interference between the surface plasmon polaritons (SPPs) modes within the six cavities. Results show that the designed structure can preferentially select the desired colors and confine the SPPS modes in one of the cavities. This designed structure can filter eleven color channels with a small full width at half maximum (FWHM) ~ 2 nm. Furthermore, the maximum values of sensitivity, figure of merit, quality factor, dipping strength, and extinction ratio can achieve of 700 nm/RIU, 350 1/RIU, 349.0, 65.04%, and 174.50 dB, respectively, revealing the excellent functions of sensor performance and optical switch, and offering a chance for designing a beneficial nanophotonic device.