Surface plasmon resonance-based fiber optic hydrogen sulphide gas sensor utilizing Cu–ZnO thin films

Abstract

We report an experimental study on a surface plasmon resonance (SPR)-based fiber optic hydrogen sulphide gas sensor with a thin metal oxide (zinc oxide (ZnO)) layer as the additional layer. This zinc oxide layer is grown over the copper layer to support surface plasmons at the metal-dielectric interface at room temperature. The wavelength interrogation mode of operation has been used to characterize the sensor. The thin film of zinc oxide over the copper film was deposited on the unclad portion of the fiber by the thermal evaporation technique. Experiments were performed for the detection of concentrations of hydrogen sulphide gas varying from 0 to 100 ppm around the probe. The unpolarized light from a polychromatic source is launched from one end of the fiber and the corresponding SPR spectrum is recorded at the other end. The recorded SPR spectrum shows a shift in the resonance wavelength on a change in the hydrogen sulphide gas concentration, which is considered as a detectable signal for the characterization of the sensor. Further, the optimization of the performance of the sensor was achieved by varying the thickness of the zinc oxide film. The sensor possesses a very fast response time and high sensitivity. Since the sensor utilizes optical fibers it has additional advantages of remote sensing, online monitoring, light weight and low cost.

Dielectric Properties of SnO2 Thin Film Using SPR Technique for Gas Sensing Applications

“…Surface Plasmon Resonance (SPR) is a powerful and sensitive technique to study the dielectric and optical properties of metal-dielectric interface, thus it can be exploited for the detection of harmful and toxic gases [1]. There are two configurations for exciting surface plasmon (SP) wave at the metal-dielectric interface: one is Otto configuration [2] and the other is Kretschmann [3] configuration.…”

Sensitive optical biosensor based on surface plasmon resonance using ZnO/Au bilayered structure

“…The sensing principle of SPR technique is the change in refractive index at the interface of metal-dielectric on exposure with the sensing material [13]. Also, sensing by SPR is advantageous because of it being room temperature operating and simple detection technique [14,15].…”

Tailoring the Field Distribution of ZnO by Polyaniline for SPR-Based Fiber Optic Detection of Hardness of the Drinking Water

“…An excellent example of such a plasmonic material is a doped semiconductor. Among the various conducting metal oxides such as TiO 2 , SiO 2 , SnO 2 , and ZnO, ZnO possesses largest oxygen vacancy over its surface 8 and hence it has highest capability to get intermixed with the other material. Also, due to the presence of dopant molecules, impure phase of dopant in the host matrix dominates which after a certain concentration becomes problematic, which is mainly due to different crystal structures of the host material as well as the dopant [13][14][15][16][17][18].…”

“…When the dielectric constant of the sensing medium is changed, the value of the resonance parameter (angle or wavelength), which corresponds to the maximum transfer of power to surface plasmons, changes and is reflected in terms of shift in the position of the dip in SPR spectrum. This phenomenon is revolutionized, in recent years, for the SPR-based chemical, biological and gas sensors utilizing prism or optical fiber as the substrate to produce evanescent wave for the excitation of surface plasmons at the metal-dielectric interface [5][6][7][8][9][10][11][12]. The most commonly used plasmonic metals for the fabrication of plasmonic sensors are silver, copper, and gold because these have large free electron densities, however, plasmonics is not limited to the metals only but any material whether conducting or semiconducting which possesses a high number of free charge carriers may exhibit plasmonic properties.…”