Fiber Optic Sensor of Ammonia Gas Using Plasmonic Extraordinary Optical Transmission

Abstract

While standard surface plasmon resonance (bio) sensing, relaying on propagating surface plasmon polariton sensitivity on homogeneous metal/dielectric boundaries, represents nowadays a routine sensing technique, other alternatives, such as inverse designs with nanostructured plasmonic periodic hole arrays, have been far less studied, especially in the context of gas sensing applications. Here, we present a specific application of such a plasmonic nanostructured array for ammonia gas sensing, based on a combination of fiber optics, extraordinary optical transmission (EOT) effect, and chemo-optical transducer selectively sensitive to ammonia gas. The nanostructured array of holes is drilled in a thin plasmonic gold layer by means of focused ion beam technique. The structure is covered by chemo-optical transducer layer showing selective spectral sensitivity towards gaseous ammonia. Metallic complex of 5-(4′-dialkylamino-phenylimino)-quinoline-8-one dye soaked in polydimethylsiloxane (PDMS) matrix is used in place of the transducer. Spectral transmission of the resulting structure and its changes under exposition to ammonia gas of various concentrations is then interrogated by fiber optics tools. The observed VIS-NIR EOT spectra are juxtaposed to the predictions performed by the rigorous Fourier modal method (FMM), providing useful theoretical feedback to the experimental data, and ammonia gas sensing mechanism of the whole EOT system and its parameters are discussed.

Optical Sensing Using Hybrid Multilayer Grating Metasurfaces with Customized Spectral Response

“…The sharp decay of the responsivity and the high values of sensitivity and FOM make the device at this wavelength suitable for sensing pressure leakage in ultrahigh-vacuum systems and for the monitoring of the air quality in closed atmospheres. In both cases, we have found a high sensitivity of the device to detect changes in the content or pressure of a closed atmosphere, which is competitive with recent approaches [52][53][54][55][56][57][58][59]. The system operates under normal incident conditions and can be micro-sized, which implies a compact platform for gas-sensing applications that can be integrated easily into different systems.…”

Response Surface Modeling of the Steady-State Impedance Responses of Gas Sensor Arrays Comprising Functionalized Carbon Nanotubes to Detect Ozone and Nitrogen Dioxide

“…Iijima's discovery of CNTs in 1991 [66] played a significant role in the evolution of nanomaterials, including nanoparticles (NPs), zeolites, nanorods, and graphene. Advances in nanotechnology have led to prolific applications in sensing, communication, and electronics spanning consumer, military, industrial, and medical use [67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83]. CNTs have been used by several researchers to demonstrate laboratory detectors for environmental gases, such as ammonia, nitrogen, NO 2 , CO 2 , etc.…”

“…Optical methods, such as plasmonic optical transmission for ammonia detection [83] and laser scattering for particulate matter (PM) detection [84], have the potential to improve accuracy and stability in environmental sensing. However, miniaturization of optical sensor systems to enable wearability is challenging, and commercially available PM sensors are predominantly handheld.…”