We experimentally demonstrate the possibility to implement an optical bio-sensing platform based on the shift of the plasmonic band edge of a 2D-periodic metal grating. Several 2D arrangements of square gold patches on a silicon substrate were fabricated using electron beam lithography and then optically characterized in reflection. We show that the presence of a small quantity of analyte, i.e. isopropyl alcohol, deposited on the sensor surface causes a dramatic red shift of the plasmonic band edge associated with the leaky surface mode of the grating/analyte interface, reaching sensitivity values of similar to 650nm/RIU. At the same time, dark field microscopy measurements show that the spectral shift of the plasmonic band edge may also be detected by observing a change in the color of the diffracted field. Calculations of both the spectral shift and the diffracted spectra variations match the experimental results very well, providing an efficient mean for the design of sensing platforms based on color observation.
Experimental Demonstration of Plasmonic-grating-Assisted Optical Biosensor / Vincenti, M. A.; Grande, M.; de Ceglia, D.; Stomeo, T.; De Vittorio, M.; Petruzzelli, V.; D'Orazio, A.; Scalora, M. (PROCEEDINGS OF SPIE, THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING). - In: Plasmonics: Metallic Nanostructures and Their Optical Properties X / [a cura di] Mark I Stockman. - STAMPA. - Bellingham WA : The international society for optics and photonics, 2012. - ISBN 978-0-8194-9174-9. [10.1117/12.929301]
Experimental Demonstration of Plasmonic-grating-Assisted Optical Biosensor
M. A. Vincenti;M. Grande;D. de Ceglia;V. Petruzzelli;A. D'Orazio;
2012-01-01
Abstract
We experimentally demonstrate the possibility to implement an optical bio-sensing platform based on the shift of the plasmonic band edge of a 2D-periodic metal grating. Several 2D arrangements of square gold patches on a silicon substrate were fabricated using electron beam lithography and then optically characterized in reflection. We show that the presence of a small quantity of analyte, i.e. isopropyl alcohol, deposited on the sensor surface causes a dramatic red shift of the plasmonic band edge associated with the leaky surface mode of the grating/analyte interface, reaching sensitivity values of similar to 650nm/RIU. At the same time, dark field microscopy measurements show that the spectral shift of the plasmonic band edge may also be detected by observing a change in the color of the diffracted field. Calculations of both the spectral shift and the diffracted spectra variations match the experimental results very well, providing an efficient mean for the design of sensing platforms based on color observation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
