Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon

Abstract

Abstract:In this work, we demonstrate experimentally the use of an array of gold nanodisks on functionalized silicon for chemosensing purposes. The metallic nanostructures are designed to display a very strong plasmonic resonance in the infrared regime, which results in highly sensitive sensing. Unlike usual experiments which are based on the functionalization of the metal surface, we functionalized here the silicon substrate. This silicon surface was modified chemically by buildup of an organosilane selfassembled monolayer (SAM) containing isocyanate as functional group. These groups allow for an easy surface regeneration by simple heating, thanks to the thermally reversible interaction isocyanate-analyte, which allows the cyclic use of the sensor. The technique showed a high sensitivity to surface binding events in gas and allowed the surface regeneration by heating of the sensor at 150°C. A relative wavelength shift ∆λ max /λ 0 = 0.027 was obtained when the saturation level was reached. 191-198 (2009). 17. K. Suyama, H. Iriyama, M. Shirai, and M. Tsunooka, "Curing systems using photolysis of carbamoyloxyimino groups and thermally regenerated isocyanate groups," J. ©2011 Optical Society of America

Experimental measurement of plasmonic nanostructures embedded in silicon waveguide gaps

“…Owing to its ultrasmall size, experimental characterization of individual nanostructures supporting plasmonic resonances is far from trivial because of the diffraction limit [7]. As a result, arrays of non-interacting metallic nanostructures created on planar substrates have been usually employed for optical characterization [8]. When measuring such arrays, several elements are simultaneously illuminated at a time.…”

Gpu Implementation of Split-Field Finite-Difference Time-Domain Method for Drude-Lorentz Dispersive Media

“…Large efforts have been done to improve the sensitivity S = Δλ/Δn (where, Δn is the change in the refractive index, expressed in Refractive Index Unit (RIU), and Δλ is the corresponding wavelength shift), and figure of merit FOM = S/FWHM (FWHM is the full width at half maximum) of plasmonic refractive index sensors. NanoDisk arrays are investigated in [51,52], the sensitivity and FOM were reported as S ∼ 178 nm/RIU, FOM ∼ 2 in [51], and S ∼ 84 nm/RIU, FOM ∼ 0.19 in [52]. Symmetric structures could not show high sensitivity and FOM.…”

“…Two major kinds of these sensors have been developed: (1) Excitation of SPR on a metallic thin film, and measuring the shift of SPR wavelength, or excitation angle, caused by changing the refractive index of surrounding medium [48]. (2) Using metallic nanoparticles in solution [49,50], or in a periodic array [51][52][53][54][55][56][57][58], and measuring the shift of LSPR resulting from the change in the refractive index of surrounding medium. The SPR sensors mainly use the attenuated total internal refraction method for plasmon excitation.…”

Design and implementation of nanoantennas on integrated guides and their application on polarization analysis and synthesis.

“…Owing to its ultrasmall size, experimental characterization of individual nanostructures supporting plasmonic resonances is far from trivial because of the diffraction limit [93]. As a result, arrays of non-interacting metallic nanostructures created on planar substrates have been usually employed for optical characterization [94]. When measuring such arrays, several elements are simultaneously illuminated at a time, and the response of an isolated element is approximated by the averaged response of the illuminated structures, with the assumption that all of them are identical.…”

“…As shown in Figure 4.1(d), illuminating a nanoantenna by two orthogonal paths would allow to modify the polarization of the scattered radiation. If it is assumed that the nanoantenna response is dominated by its in-plane electric dipolar resonance -which is the case of subwavelength thin metallic disks [94]-then both paths will excite orthogonal transversal dipoles. Then, under a  phase difference, circular polarization in the direction of the disk axis becomes attainable, even though the nanoantenna is not chiral.…”