Analytical Approach to Realize Locally Integrated Absorption of Metal-Dielectric-Metal Plasmonic Metasurfaces

• Published in: Plasmonics (Norwell, Mass.) Mass.), 2023-08, Vol.18 (4), p.1297-1305
• Main Authors: Nguyen, Xuan Bach, Nguyen, Huu Tu, Hoang, Thu Trang, Pham, Thanh Son, Le, Khai Q., Ngo, Quang Minh
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Biochemistry; Biological and Medical Physics; Biophysics; Biotechnology; Chemistry; Chemistry and Materials Science; Finite difference time domain method; Mathematical analysis; Medical imaging; Metasurfaces; Nanotechnology; Numerical models; Optical properties; Plasmonics; Silicon dioxide; Silicon substrates; Silver; Surface chemistry; Surface plasmon resonance
• ISSN: 1557-1955; 1557-1963
• DOI: 10.1007/s11468-023-01839-4

This work theoretically introduces an analytical approach to understand the local absorptions of the metal-dielectric-metal (MDM) plasmonic metasurfaces of silver (Ag) subwavelength disk arrays on a stack of thin silica (SiO 2 ) spacing layer and Ag film (acting as a reflector) on silicon (Si) substrate. Poynting’s theorem has been used to determine exactly the local absorption using the integration of the elemental absorption power density over the interested parts of the structure. The proposed analytical method is verified by a numerical model of the absorbed energy of the MDM plasmonic metasurfaces using the finite-difference time-domain method. Our analysis on the local absorption is able to reveal the intensive optical properties such as the absorption concentrated anywhere in the MDM plasmonic metasurfaces. At surface plasmon resonances, the absorption at the bottom half of the Ag disk region is the main contribution to the total loss of the structure. Knowing the exact absorption at any region of any structure is a key for the advanced study of biosensing and bioimaging, surface-enhanced absorption spectroscopy, and quantum communication.