Resonance Optical Sensor Research Articles

A Surface Plasmon Resonance Optical Fiber Sensor for Simultaneous Measurement of Relative Humidity and Temperature

In this work, a new method was explored for developing temperature and relative humidity (RH) optical fiber sensors based on surface plasmon resonance (SPR). A SPR optical fiber sensor coated with carboxymethyl cellulose (CMC) and polydimethylsiloxane (PDMS) was proposed for the simultaneous measurement of RH and temperature. The sensor was fabricated by connecting two no-core optical fibers (NCFs) using multimode optical fibers (MMFs). Metal films were deposited on the surface of NCFs and further coated with CMC and PDMS. CMC coating was used for RH sensing based on the change of refractive index (RI) caused by water absorption; PDMS coating was used for temperature sensing based on its RI change with temperature. Univariate analysis showed that there was very weak interaction between RH and temperature measurement. For RH sensing, the sensitivities were −1.230 nm/RH%, −2.932 nm/RH% and −0.431 nm/RH% when RH were 50%~65%, 65%~70% and 70%~80%, respectively; for temperature sensing, the sensitivity was −2.213 nm/°C at 10 °C~50 °C. The proposed sensor can not only respond to both temperature and RH variation, but also compensate the cross sensitivity between the two parameters. It is simple in structure, easy to manufacture and efficient in the simultaneous detection of temperature and RH, which promises great application prospects in the fields of agriculture, food industry, biological field and other production activities.

Design and analysis of highly sensitive prism based surface plasmon resonance optical salinity sensor

This research presents a highly sensitive surface plasmon resonance (SPR) optical salinity sensor based on angular interrogation method for the quantification of salinity and desalination of sea water. The proposed salinity sensor structure composed of prism-silver (Ag)-silicon (Si)-Franckeite-sensing medium. To achieve the best possible performance i. e. sensitivity, detection accuracy, and quality factor, the sensor is designed and simulated at different wavelengths of 633 nm, 643.8 nm, 690 nm, 700 nm, and 720 nm. The performance of the sensor has also been optimized for different thickness of Ag layer, Si layer, and no. of layer of 2D franckeite. An enhanced maximum sensitivity of 305 deg./RIU is obtained with detection accuracy 0.41 deg.−1 and quality factor 63.92 RIU−1. As the sensor provides high grade of performance, this can be used as a salinity sensor for the desalination of seawater.

Fundamental sensitivity bounds for quantum enhanced optical resonance sensors based on transmission and phase estimation

Quantum states of light can enable sensing configurations with sensitivities beyond the shot-noise limit. In order to better take advantage of available quantum resources and obtain the maximum possible sensitivity, it is necessary to determine fundamental sensitivity limits for different possible configurations for a given sensing system. Here, due to their wide applicability, we focus on optical resonance sensors, which detect a change in a parameter of interest through a resonance shift. We compare their fundamental sensitivity limits set by the quantum Cramér–Rao bound (QCRB) based on the estimation of changes in transmission or phase of a probing bright two-mode squeezed state (bTMSS) of light. We show that the fundamental sensitivity results from an interplay between the QCRB and the transfer function of the system. As a result, for a resonance sensor with a Lorentzian lineshape a phase-based scheme outperforms a transmission-based one for most of the parameter space; however, this is not the case for lineshapes with steeper slopes, such as higher order Butterworth lineshapes. Furthermore, such an interplay results in conditions under which the phase-based scheme provides a higher sensitivity but a smaller degree of quantum enhancement than the transmission-based scheme. We also study the effect of losses external to the sensor on the degree of quantum enhancement and show that for certain conditions, probing with a classical state can provide a higher sensitivity than probing with a bTMSS. Finally, we discuss detection schemes, namely optimized intensity-difference and optimized homodyne detection, that can achieve the fundamental sensitivity limits even in the presence of external losses.

Surface plasmon resonance optical sensor for COVID-19 detection

The transmission of SARS-CoV-2, the novel severe acute respiratory syndrome corona virus have caused the corona virus disease (Covid-19) worldwide pandemic. Overcoming this pandemic requires identifying patients to avoid further spread of the disease. Real-time, sensitive, and cost-efficient methods for detecting the COVID-19 virus are crucial. Optical sensors provide one such means to achieve this, especially using surface plasmon resonance due to its advantages such as high sensitivity and excellent detection limits. In this paper, we propose a sensor for COVID-19 detection which is based on a simple Kretschmann configuration with gold layers and thiol-tethered DNA for the ligand layer. Angle interrogation was used to obtain the sensitivity of this structure using Matlab numerical analysis. The performance of the sensor was investigated with two types of prisms, SF10 and SF11, while varying the gold layer thickness between 45 - 60 nm. This information was then used to determine which combination of prism and gold thickness are ideal for detecting COVID-19 using thiol-tethered DNA. Thiol-tethered DNA layer sensor showed the highest sensitivity of 137 degree/RIU when a SF10 prism was used with a 50 - 60 nm gold layer and thiol tethered DNA layer.

Overview of surface plasmon resonance optical sensors for Covid-19 (SARS-CoV-2) detection

The SARS-CoV-2 i.e., the novel severe acute respiratory syndrome corona virus; has caused massive loss of life. Mitigating this pandemic requires rapid inexpensive technologies for testing COVID-19. Optical sensors can be used to detect the Covid-19 virus by the surface Plasmon resonance phenomenon. Surface plasmon resonance sensors have good sensitivity, response times, fine resolution, and limits of detection. This paper, provides a brief overview on the COVID-19 effects, currently used testing technology, and potential of surface plasmon resonance optical sensors use for detecting this virus.

Ag-Ni bimetallic film on CaF2 prism for high sensitive surface plasmon resonance sensor

Ag-Ni bimetallic film on CaF2 prism for high sensitive surface plasmon resonance sensor

Enhanced red emission of Yb, Ho: NaYGd(WO4)2 phosphors by codoping Ce3+

In this work, Yb, Ho, Gd3+/Gd3+, Ce3+: NaY(WO4)2 phosphors doped with various concentrations of Gd3+ and Ce3+ ions were prepared via high-temperature solid-state method. Under the excitation of 980 nm near-infrared light, the doping of Gd3+ ions enhances the red and green emission of Yb, Ho: NaY(WO4)2, and on this basis, the Y3+ ion is replaced by Ce3+ ion doping, the red upconversion emission intensity was enhanced with Ce3+ concentration increasing. It was found that two efficient cross-relaxation processes between Ho3+ and Ce3+ ions had been employed to enhance red emission and suppress green emission. The possible upconversion mechanisms between Ho3+ and Ce3+ ions were investigated in detail. Yb3+, Ho3+, Gd3+, Ce3+ co-doped NaY(WO4)2 phosphors have broad application prospects in the fields of anti-counterfeiting and display, magnetic resonance imaging and optical temperature sensors.

Polymer Optical Microcavity Sensor for Volatile Organic Compounds with Distinct Selectivity toward Aromatic Hydrocarbons

A whispering-gallery mode (WGM) optical resonance sensor for volatile organic compounds (VOCs) is developed from polystyrene (PS) microspheres doped with fluorescent β-cyano-appended oligo(p-phenylenevinylene) (β-COPV). The β-COPV-doped PS microspheres (MSCOPV) are formed by the miniemulsion method in a binary solvent. MSCOPV expand upon permeation of VOCs into the PS matrix and exhibit a spectral shift of the WGM resonance peak. The permeation efficiency is highly dependent on the chemical affinity between the analyte and the polymer matrix, with exceptionally high selectivity toward aromatic hydrocarbons such as benzene, toluene, and xylenes (BTXs). The high selectivity and sensitivity of MSCOPV are in clear contrast to those of conventional WGM sensors that just detect VOCs nonpreferentially through adsorption onto the surface.

Effect of PMMA Removal Methods on Opto-Mechanical Behaviors of Optical Fiber Resonant Sensor With Graphene Diaphragm

Regarding the dependence of the treatment of removing polymethyl methacrylate (PMMA) from graphene upon the prestress in the film, two typical PMMA removal methods including acetone-vaporing and high-temperature annealing were investigated based on the opto-mechanical behaviors of the developed optical fiber Fabry-Perot (F-P) resonant sensor with a 125-µm diameter and ∼10-layer-thickness graphene diaphragm. The measured resonant responses showed that the F-P sensor via annealing process exhibited the resonant frequency of 481 kHz and quality factor of 1 034 at ∼2 Pa and room temperature, which are respectively 2.5 times and 33 times larger than the acetone-treated sensor. Moreover, the former achieved a high sensitivity of 110.4 kHz/kPa in the tested range of 2 Pa–2.5 kPa, apparently superior to the sensitivity of 16.2 kHz/kPa obtained in the latter. However, the time drift of resonant frequency also mostly tended to occur in the annealed sensor, thereby shedding light on the opto-mechanical characteristics of graphene-based F-P resonant sensors, along with an optimized optical excitation and detection scheme.

Design of reflectivity-based surface plasmon resonance optical sensors for ultrasound detection

Sensors based on surface plasmon resonance present attractive features for the detection of narrow acoustic pulses since they can behave as quasi-point detectors. In order to detect fast ultrasound pressure waves, the system senses the intensity of the reflected beam for a fixed angle of incidence and for a fixed wavelength. Therefore, optimal conditions for Kretschmann's glass-metal-water configuration are presented. Optimization is performed by means of numerical simulations of the reflectivity curves for different low-cost metallic films with different thicknesses and angles of incidence. Zn, Ti, Cr, Al, and Cu are evaluated and compared with Au. In addition, the wavelength selection is discussed, and the oxidation effects are also briefly analysed.

Dithiol Self-Assembled Monolayer Based Electrochemical Surface Plasmon Resonance Optical Fiber Sensor for Selective Heavy Metal Ions Detection

Herein, we report the simultaneously application of surface plasmon resonance (SPR) spectroscopy and electrochemistry (EC) technology for the real-time quantitative investigation of heavy metal ions, with high selectivity and sensitivity. A surface of optical fiber coated over with nanometric gold film and then modified with a dithiol self-assembled monolayer of 1,6-hexanedithiol (HDT) was developed as the dual mode electrochemical-surface plasmon resonance (EC-SPR) optical fiber sensor. The limit of detection of the proposed sensor exposed in Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions solution without and with the multiple cyclic voltammetry (CV) scans to activate the HDT monolayer can be improved from 0.47 μM to 0.22 μM. More importantly, the CV scans can activate the redox reaction of Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions, and then easily strip the Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions from the HDT monolayer to restore the active sites, and endow the designed sensor the characteristics of repeated use. Under simultaneous SPR monitoring, the differential pulse voltammetry (DPV) currents of HDT-functionalized optical fiber can also act as a microelectrode to develop electrochemical sensor platform for monitoring Cu <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> , with a limit of detection of 94 nM and a dynamic range up to 90 μM. As a comparison, the EC-SPR sensor still has good analysis performance for both Hg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> and Cu <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions in presence of Ni <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> , Fe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> , Co <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> , Pb <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> , K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> , among others. We therefore demonstrated that the proposed fiber-based EC-SPR sensor has the advantages of real-time, miniaturized, and cost-effective sensing, paving the way for environmental monitoring applications for on site inspection.

High-Performance coupled plasmon waveguide resonance optical sensor based on SiO2:Ag film

A coupled plasmon waveguide resonance (CPWR)-based optical sensor takes advantage of the evanescent wave at a waveguide boundary to excite surface plasmon polaritons, which can link waveguide electromagnetic energy to a surface plasmon wave to enhance the propagating surface plasmon resonance. Herein, a novel optical sensor having a BK7 prism/Ag/SiO2/SiO2:Ag structure and that couples the localised surface plasmon resonance of Ag nanoparticles in a SiO2 film was designed and fabricated. The results showed that the proposed sensor exhibited higher sensitivity (~1396.85 nm RIU−1) and figure of merit (~11.36 RIU−1) values than a traditional CPWR optical sensor (i.e., 368.50 nm RIU−1 and 1.72 RIU−1, respectively). Moreover, the resonance wavelength could be tuned to the near-infrared region by adjusting the thickness of the SiO2 interlayer or the Ag content of the top SiO2 layer. Simulations and experimental data confirmed that the CPWR-based sensor exhibited superior optical sensing performance.

No-core optical fiber sensor based on surface plasmon resonance for glucose solution concentration and temperature measurement.

The accuracy of the surface plasmon resonance (SPR) optical fiber sensor is affected by the change of ambient temperature. Therefore, we propose a simple dual channel SPR optical fiber sensor, which can measure both glucose concentration and ambient temperature. The proposed sensor is a two-channel structure based on a no-core optical fiber (NCF): one channel is coated with gold film and polydimethylsiloxane (PDMS) to sense the ambient temperature, and the other is coated with silver film to sense glucose concentration. The experimental results show that the sensor's sensitivity for sensing glucose concentration is 2.882 nm / %, and for sensing temperature is -2.904 nm / °C. By monitoring the real-time temperature, the accuracy of glucose concentration detection was improved. The proposed sensor has a simple and compact structure, and it is suitable for sensing glucose solution or other analyte solutions that need temperature compensation.

Characterization of Otto Chips by Particle Swarm Optimization

Abstract Recently a surface plasmon resonance (SPR) optical sensor, based on the Otto configuration — the Otto chip — has been developed. One essential step in the quality control of the fabrication process is characterization of the active region of several devices in a batch. Characterization is done by measuring the angular spectrum of the optical re ectance on several points across the active region of the device, and determining parameters by regression analysis of the data. Traditional gradient methods used in the regression process are extremely dependent on an initial guess and are not very efficient for batch analysis of curves, when those include poorly defined SPR spectra, where an initial guess may be hard to infer. An alternative approach for the regression problem is to model the analysis as an optimization problem and using an efficient stochastic algorithm. In this paper one discusses the use of Particle Swarm Optimization (PSO) for characterization of Otto chip devices. From comparative studies carried out in an existing Otto chip, it is observed that PSO can be a very efficient approach for batch analysis and yields better results when compared with the traditional gradient-based regression method.

An Optical Sensor for Dengue Envelope Proteins Using Polyamidoamine Dendrimer Biopolymer-Based Nanocomposite Thin Film: Enhanced Sensitivity, Selectivity, and Recovery Studies.

This paper proposes a novel idea to enhance the sensitivity and selectivity of surface plasmon resonance (SPR) optical sensor for detection of dengue virus type-2 envelope proteins (DENV-2 E-proteins) using polyamidoamine (PAMAM) dendrimer biopolymer-based nanocomposite thin film. For this purpose, two ranges of DENV-2 E-protein concentrations, i.e., 0.000008–0.0001 nM and 0.00008–0.005 nM were evaluated, and the lowest detectable concentration was achieved at 0.00008 nM. The incorporation of PAMAM dendrimer-based nanocomposite thin film with an SPR sensor exhibited a significant increase in sensitivity and binding affinity to a lower range DENV-2 E-protein concentrations. Moreover, the proposed sensor displayed good selectivity towards DENV-2 E-proteins and have an average recovery of 80–120%. The findings of this study demonstrated that PAMAM dendrimer-based nanocomposite thin film combined with SPR sensor is a promising diagnostic tool for sensitive and selective detection of DENV-2 E-proteins.

X-ray Photoelectron Spectroscopy Analysis of Chitosan-Graphene Oxide-Based Composite Thin Films for Potential Optical Sensing Applications.

In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan–graphene oxide (chitosan–GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR–chitosan–GO thin film, while for CdS QD–chitosan–GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian–Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan–GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR–chitosan–GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.

New Trends in Optical Resonant Bio-Chemical Sensing

The development of innovative bio-chemical sensors is of great importance to make new devices available to the market. In the current paper, we review recent trends on optical resonant sensors that may involve plasmonic or geometrical resonances. In all cases, resonance is activated by excitation with electromagnetic light of proper wavelength. Plasmonic hot electrons, obtained by shining light on metal nanoparticle decorated metal oxides, can bring new effects in physicochemical processes, affecting electrical and optical properties (absorption/transmission, Surface Enhanced Raman Spectroscopy SERS). Geometrical resonances are involved in Mie and Whispering Gallery Modes (WGM) based sensing, including metasurfaces for optical detection of molecules and nonlinear effects in metamaterials.

Recent Advances in Surface Plasmon Resonance Optical Sensors for Potential Application in Environmental Monitoring

Recent Advances in Surface Plasmon Resonance Optical Sensors for Potential Application in Environmental Monitoring

Comparison between one layer and bilayer surface plasmon resonance optical fiber chemical sensor

Surface Plasmon Resonance (SPR) - based plastic optical fiber has been provided as a sensor to estimate the refractive index and then the concentration of specific chemical samples. Two configurations were suggested for the design. The first was through using a single layer of gold with a thickness of about 40nm deposited on a 10mm portion in the middle of plastic optical fiber. In the second configuration, a bilayer is deposited on the fiber. This bilayer consisted of a gold layer with a thickness of about 30 nm and an aluminum layer with a thickness of about 30 nm. Both of these configurations are utilized as chemical sensors. The resonance wavelength for the bilayer-based sensor was higher than that of the single-layer sensor for all studied chemical samples. The highest resonance wavelength was for the salt-water solution with a concentration of 30%. For the salt-water solution with a concentration of 30%, the resonance wavelength with the bilayer-based sensor was 568nm while it was 540nm with the single-layer sensor.

X-ray photoelectron study on gold/nanocrystalline cellulose-graphene oxide thin film as surface plasmon resonance active layer for metal ion detection

X-ray photoelectron spectroscopy (XPS) is a spectroscopic technique that is surface-sensitive that can be used to analyze the chemical and elemental state of a sample on the surface. In this research, XPS was used to study the chemical interaction of gold/nanocrystalline cellulose-graphene oxide (gold/NCC-GO) thin film. The thin film was prepared by deposition of NCC-GO on a gold thin film using spin coating method to obtain a homogeneous gold/NCC-GO thin film before characterized by XPS. From the XPS results, it is confirmed that carbon, oxygen, nitrogen, and sulfur elements exist on the gold/NCC-GO thin film surface. Further deconvolution has also been carried out by Voigt curve fitting program in order to determine the sub-peak component of each elements. Besides that, the gold/NCC-GO thin film has potential to be used in sensing metal ion application. The interaction of metal ions with the gold/NCC-GO thin film was optically proven using surface plasmon resonance optical sensor before the thin film was characterized again by XPS to confirm the chemical interactions involved. It is believed that the existence negative charge functional groups, i.e., COO− and SO3− on the gold/NCC-GO thin film surface played an important role during the interaction.