scholarly journals A Polarization-Independent Fiber-Optic SPR Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3204 ◽  
Author(s):  
Songquan Li ◽  
Laixu Gao ◽  
Changwei Zou ◽  
Wei Xie ◽  
Yong Wei ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Chemical Sensors ◽  
Fiber Optic ◽  
High Sensitivity ◽  
Sample Volume ◽  
High Signal ◽  
Wavelength Modulation ◽  
Plasmon Excitation ◽  
Spr Sensor ◽  
Polarization Independent

Fiber-optic surface plasmon resonance (SPR) sensors possess the advantages of small size, flexible, allowing for a smaller sample volume, easy to be integrated, and high sensitivity. They have been intensively developed in recent decades. However, the polarizing nature of the surface plasmon waves (SPWs) always hinders the acquisition of SPR spectrum with high signal-noise ratio in wavelength modulation unless a polarizer is employed. The addition of polarizer complicates the system and reduces the degree of compactness. In this work, we propose and demonstrate a novel, polarization-independent fiber-optic SPR sensor based on a BK7 bi-prism with two incident planes orthogonal to each other. In the bi-prism, TM-polarized components of non-polarized incident lights excite SPWs on the first sensing channel, meanwhile the TE components and the remaining TM components are reflected, then the reflected TE components serve as TM components of incident lights for the second sensing channel to excite SPWs. Simulations show the proposed SPR structure permit us to completely eliminate the polarization dependence of the plasmon excitation. Experimental results agree well with the simulations. This kind of devices can be considered an excellent option for development of simple and compact SPR chemical sensors.

Comparing high-sensitivity geophones to fiber-optic DAS technologies in a hard-rock VSP survey

2020 ◽  
Author(s):  
Björn Lund ◽  
Anna Stork ◽  
Michael Roth ◽  
Ari David ◽  
Andy Clarke ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Transfer Functions ◽  
Incidence Angle ◽  
High Sensitivity ◽  
Gauge Length ◽  
Signal Frequency ◽  
Nuclear Waste Repository ◽  
High Signal ◽  
Frequency Content ◽  
Velocity Signal

<p>As part of the preparations for a microseismic network on the planned nuclear waste repository in Forsmark, Sweden, we carried out a suite of measurements for site characterisation and instrument testing using geophones and DAS fiber-optic technology. Three high-sensitivity 240 V/m/s geophones were grouted into a 200 m deep borehole together with a linear, a helical and a helical engineered fiber-optical cable. Two different interrogators were used for DAS acquisition. We performed a walk-away vertical seismic profile (VSP) survey with 10 m source spacing out to 1.1 km offset and compare the responses of the four different measurement systems. The complete transfer functions of the fiber-optic systems have not yet been determined, and depend on factors such as incidence angle, signal frequency content and the fiber gauge length. Preliminary results show that all systems record signals with high signal-to-noise ratio and that which system has highest performance depends on source-receiver distance, signal frequency content and wave incidence angle. Due to incomplete knowledge of the fiber transfer functions we cannot match the DAS velocity signal with the geophone signal. Investigation of the detection capabilities of the fiber and geophone systems is underway and will be presented together with a discussion of the relative merits of the various systems for microseismic monitoring.</p>

scholarly journals Direct Electrical Detection of sub-aM DNA Concentrations

2020 ◽  
Author(s):  
Maoxiang Guo ◽  
Narayanan Madaboosi ◽  
Felix Neumann ◽  
Mats Nilsson ◽  
Wouter van der Wijngaart
Keyword(s):  
Mass Transport ◽  
Spatial Scales ◽  
High Sensitivity ◽  
High Specificity ◽  
Sample Volume ◽  
High Signal ◽  
Gold Nanowires ◽  
Detection Zone ◽  
Large Sample ◽  
Target Molecules

AbstractSensors for detecting ultra-low concentrations are limited by the efficient transport of target molecules from large sample volumes to small detection regions. We here report a small-format digital DNA sensor in the shape of a microporous membrane that electrically detects DNA substrates with a concentration as low as 790 zM. This ultra-high sensitivity follows from optimising the mass transport of target DNA to specific receptors on the membrane across multiple spatial scales. mm-sized membranes support the rapid convection of a large sample volume to the detection zone; µm-sized pores ensure that DNA diffusion to the surface-based receptors dominates over convective loss through the pores (low Péclet number), and; at the nm-scale, target-receptor binding dominates over diffusive transport (high Damköhler number). After their efficient capture, the DNA molecules are converted with high specificity into trans-membrane gold nanowires that are detected using a simple, high signal-to-noise, electrical resistance measurement. This sensor design is of interest for detecting low-abundant target molecules without the need for sample amplification or up-concentration, and the mass-transport strategy could be adapted to other surface-based sensing schemes.

scholarly journals Surface plasmon assisted toxic chemical NO<sub>2</sub> gas sensor by Au ∕ ZnO functional thin films

2021 ◽  
Vol 10 (2) ◽  
pp. 163-169
Author(s):  
Ravinder Gaur ◽  
Himanshu Mohan Padhy ◽  
Manikandan Elayaperumal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Surface Plasmon ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Film Material ◽  
Hybrid Thin Film ◽  
Spr Sensor

Abstract. In this short communication, we propose a surface plasmon resonance (SPR) sensor based on a ZnO / Au hybrid thin-film material structure and experimentally investigate its sensitivity improvement. The Kretschmann-based SPR sensor utilizes ZnO thin films and nanostructures for performance enhancement. The advancement in SPR technology relies on a low-cost, high-sensitivity, and high-selectivity sensor. Metal oxide (MO) has been incorporated into the SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecule detection depends on their interaction with the ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In the future, the thin film and nanostructures of ZnO could be a potential application for miniature design, robust, high sensitivity, and a low-cost portable type of SPR biosensor to be used for on-site testing in a real-time and label-free manner. The present work includes the application of a developed SPR setup for gas sensing at room temperature using a specially designed gas cell. The change in the optical properties of dielectric layers (ZnO) with adsorption of gases (NO2) in order to develop an optical sensor has been presented. The obtained results emphasize the applications of an SPR setup for the study of interaction of adsorbed gas molecules, with dielectrics and gas sensing.

Barium titanate film based fiber optic surface plasmon sensor with high sensitivity

2020 ◽  
Vol 124 ◽  
pp. 105899 ◽  
Author(s):  
Qi Wang ◽  
Li-Ye Niu ◽  
Jian-Ying Jing ◽  
Wan-Ming Zhao
Keyword(s):  
Barium Titanate ◽  
Surface Plasmon ◽  
Fiber Optic ◽  
High Sensitivity

scholarly journals Fiber-Optic Localized Surface Plasmon Resonance Sensors Based on Nanomaterials

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 819
Author(s):  
Seunghun Lee ◽  
Hyerin Song ◽  
Heesang Ahn ◽  
Seungchul Kim ◽  
Jong-ryul Choi ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Fiber Optics ◽  
Surface Plasmon ◽  
Chemical Reactions ◽  
Plasmon Resonance ◽  
Localized Surface Plasmon Resonance ◽  
Fiber Optic ◽  
High Sensitivity ◽  
Review Article ◽  
Localized Surface Plasmon

Applying fiber-optics on surface plasmon resonance (SPR) sensors is aimed at practical usability over conventional SPR sensors. Recently, field localization techniques using nanostructures or nanoparticles have been investigated on optical fibers for further sensitivity enhancement and significant target selectivity. In this review article, we explored varied recent research approaches of fiber-optics based localized surface plasmon resonance (LSPR) sensors. The article contains interesting experimental results using fiber-optic LSPR sensors for three different application categories: (1) chemical reactions measurements, (2) physical properties measurements, and (3) biological events monitoring. In addition, novel techniques which can create synergy combined with fiber-optic LSPR sensors were introduced. The review article suggests fiber-optic LSPR sensors have lots of potential for measurements of varied targets with high sensitivity. Moreover, the previous results show that the sensitivity enhancements which can be applied with creative varied plasmonic nanomaterials make it possible to detect minute changes including quick chemical reactions and tiny molecular activities.

Sign in / Sign up

Export Citation Format

Share Document