Fiber Optic Spectrometer Research Articles

Investigation of Optical Spectroscopic Properties on Fluorescent Creams

The optical spectroscopic properties of fluorescent materials were investigated using laser induced fluorescence technique. The fluorescent creams were used in this research. The sample materials were illuminated by UV laser excitation source. Then, the fluorescence spectra were recorded and analyzed by fiber optics spectrometer complied with the CIE 1931 XYZ color space which is essential for color management. The result showed that the characteristics of fluorescence spectra such as intensity, wavelength position and bandwidth in each fluorescent creams exhibited distinct characteristics in each species.

Light output from six battery operated dental curing lights

Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p<0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p<0.01). The Bluephase G2 and Translux 2Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs.

Influence of boron concentration on nonlinear absorption and ultrafast dynamics in GaSe crystals

The nonlinear absorption properties and ultrafast dynamics of pure and boron doped GaSe crystals have been studied by open aperture Z-scan and ultrafast pump probe spectroscopy techniques. All of the studied crystals showed nonlinear absorption under 100 fs pulse duration and 1200 nm wavelength excitations. Nonlinear absorption coefficients increase with increasing the doping ratio of boron atoms in crystals. These findings indicate that free carrier density increase with boron doping and this behavior leads to excited state absorption. Second harmonic generation signals of crystals were detected with the help of fiber optic spectrometer. The blue shift in the energy of the second harmonic generation signals was observed in boron doped crystals. Ultrafast pump probe experiments indicate that the excited state absorption signal with long lifetime observed for undoped GaSe crystal switches to bleach signal for boron doped GaSe crystals at 625 nm probe wavelength. The effects of increasing doping ratio were observed on ultrafast dynamics as a switching time changes. Our experimental results indicate that it is possible to control nonlinear absorption properties, frequency conversion and ultrafast dynamics of GaSe crystal by changing boron doping ratio.

In vivosubsite classification and diagnosis of oral cancers using Raman spectroscopy

Oral cancers suffer from poor disease-free survival rates due to delayed diagnosis. Noninvasive, rapid, objective approaches as adjuncts to visual inspection can help in better management of oral cancers. Raman spectroscopy (RS) has shown potential in identification of oral premalignant and malignant conditions and also in the detection of early cancer changes like cancer-field-effects (CFE) at buccal mucosa subsite. Anatomic differences between different oral subsites have also been reported using RS. In this study, anatomical differences between subsites and their possible influence on healthy vs pathological classification were evaluated on 85 oral cancer and 72 healthy subjects. Spectra were acquired from buccal mucosa, lip and tongue in healthy, contralateral (internal healthy control), premalignant and cancer conditions using fiber-optic Raman spectrometer. Mean spectra indicate predominance of lipids in healthy buccal mucosa, contribution of both lipids and proteins in lip while major dominance of protein in tongue spectra. From healthy to tumor, changes in protein secondary-structure, DNA and heme-related features were observed. Principal component linear discriminant analysis (PC-LDA) followed by leave-one-out-cross-validation (LOOCV) was used for data analysis. Findings indicate buccal mucosa and tongue are distinct entities, while lip misclassifies with both these subsites. Additionally, the diagnostic algorithm for individual subsites gave improved classification efficiencies with respect to the pooled subsites model. However, as the pooled subsites model yielded 98% specificity and 100% sensitivity, this model may be more useful for preliminary screening applications. Large-scale validation studies are a pre-requisite before envisaging future clinical applications.

The effect of storage to optical properties in case of two apple fruit varieties

The keeping quality of fruits is a very important factor in storage point of view, since it could be elongated the consumption time of fruits. In many cases the storage may be necessary, e.g. in short time it is not able to market due to the rich harvest, or all fruits could sell in markets throughout the year. The keeping quality of various fruit species is greatly different; moreover it could be observed some differences between the varieties as well. In our research, we have investigated the spectral properties of the external surface and fl esh of two ripe apple varieties – Jonagored and Granny Smith – before and after storage (about 3°C and about three weeks). The hyperspectral investigation was carried out with AvaSpec-2048 Fiber Optic Spectrometer. The experimental results represented the differences between healthy and chilling injured apple fruits. Furthermore, some indices were created to given countenance to the spectral differences.

Real-Time, Online Automated System for Measurement of Water-Soluble Reactive Phosphate Ions in Atmospheric Particles.

We present a novel automated system for real-time measurements of water-soluble reactive phosphate (SRP) ions in atmospheric particles. Detection of SRP is based on molybdenum blue chemistry with Sn(II) chloride dihydrate reduction. The instrumentation consists of one particle-into-liquid sampler (PILS) coupled with a 250 cm path length liquid waveguide capillary cell (LWCC) and miniature fiber optic spectrometer, with detection wavelength set at 690 nm. The detection limit was 0.4 nM P, equivalent to 0.03 nmol P m(-3) in atmospheric particles. Comparison of SRP in collocate PM2.5 aerosol filter sampling with the PILS-LWCC on line system were in good agreement (n = 49, slope = 0.84, R(2) = 0.78). This novel technique offers at least an order of magnitude enhancement in sensitivity over existing approaches allowing for SRP measurements of unprecedented frequency (8 min), which will lead to greater understanding of the sources and impacts of SRP in atmospheric chemistry.

Transmission of violet and blue light through conventional (layered) and bulk cured resin-based composites

ObjectivesThis study measured the transmission of light in the ‘violet’ (350≤λ≤425nm) and ‘blue’ (425<λ≤550nm) spectral ranges from a polywave® LED curing light through different thicknesses of four commercial, resin-based composites (RBCs). Material and methodsSamples of conventional layered RBCs (Tetric EvoCeram A2, Filtek Supreme Ultra A2B), and bulk-curing resins (Tetric EvoCeram Bulk Fill IVA, and SureFil SDR Flow U) were prepared. Three samples of each RBC were made at thicknesses of 0.1, 0.7, 1, 2, and 4-mm. The uncured RBC specimens were affixed at the entrance aperture of a 6-inch integrating sphere and light-cured once for 20s using a polywave® LED curing light (Bluephase G2) on its high power setting. The spectral radiant power transmitted through each RBC in the ‘violet' and ‘blue' regions was measured using a fiberoptic spectrometer. ResultsAs RBC thickness increased, an exponential attenuation of transmitted light was measured (R2>0.98). Attenuation was greater for the ‘violet’ than for the ‘blue’ spectral regions. At the light tip, the violet light component represented 15.4% of the light output. After passing through 4-mm of RBC, the violet light represented only between 1.2–3.1% of the transmitted light depending on the RBC. Depending on RBC, approximately 100mW from the Bluephase G2 was transmitted through 0.1-mm of RBC in the ‘violet’ range, falling at most to 11mW after passing through 2-mm of RBC, and to only 2mW at 4-mm depth. ConclusionsIncreasing RBC thickness results in an exponential decrease in light transmission. This attenuation is RBC-dependent with shorter wavelengths (violet) attenuated to a greater extent than longer wavelengths (blue). Clinical relevanceDespite the increased translucency of bulk curing RBCs, spectral radiant power shorter than 425nm from a curing light is unlikely to be effective at a depth of 4-mm or more.

Analysis of photoluminescence decay kinetics of aluminum phthalocyanine nanoparticles interacting with immune cells

This work is dedicated to the study of the photoluminescence kinetics of aluminum phthalocyanine nanoparticles in colloidal solutions at different pH and in the interaction with immune cells (macrophages). For measurements we used a registration system based on Hamamatsu streak camera (C10627-13 Hamamatsu Photonics) with picosecond temporal resolution (15 ps), conjugated with the fiberoptic spectrometer and picosecond laser pumping. The changes in fluorescence decay kinetics as additional lifetime components of fluorescence were found during the experiment. The number of components and duration of lifetimes changed while interacting with cells and depends on pH. At pH 2 the presence of two fluorescence lifetimes was recorded: the first one was 5 ns, which corresponded to the molecular form in solution, and 1.5 ns, which corresponded to bound state of phthalocyanine molecules. Due to the absence of other possible objects for bounding in the solution except of the nanoparticles we can suggest with a high degree of accuracy that the bounding occurs with the very these nanoparticles. Analysis of the fluorescence lifetimes of aluminum phthalocyanine nanoparticles in macrophages indicated the presence of two components: 9 ns and 4.5 ns. A model of surface molecules transitions from parallel to perpendicular position, regarding to the plane of the crystal nanoparticle was proposed.

Physiological response of locusts to eye stimulation by spectral illumination for phototactic pest control

To provide theoretical support for study of locust phototactic vision nature, the locust phototactic physiology and visual spectrum effects were investigated by stimulating the visual system using light from an AvaSpec fiber-optic spectrometer and Flir thermal imaging system. When light stimulated the locust visual system, the biological photoelectric transformation effect of the visual system caused by photon energy, presented with the higher physiological temperature on the forehead, as tested by the Flir thermal system. After stimulation with light, the different absorption degrees of the vision system on the spectral photons, as tested by the AvaSpec spectrometer, showed that the phototactic response to light had the simultaneous requirements of lighting intensity and time. The absorbing differences of spectral photons by the vision system demonstrated the absorption selectivity under light stimulation, as exhibited by the sensitive absorption of spectral energy at 430 nm, 545 nm and 615 nm. Moreover, the higher forehead temperature increment indicated and induced the stronger physiology activity which was the reason that causing the good phototactic response degree of locusts with 30 min light stimulation, and the adaption time was about 60 min. Therefore, only when the visual reaction effect was stimulated to absorb sensitive spectral energy and generate the physiological exciting response could cause the phototactic behavior. Keywords: Phototactic pest control, physiological response, Locusta migratoria, spectral illumination, phototactic vision, spectrum absorption, light simulation DOI: 10.3965/j.ijabe.20160902.1249 Citation: Liu Q H, Zhou Q. Physiological response of locusts to eye stimulation by spectral illumination for phototactic pest control. Int J Agric & Biol Eng, 2016; 9(2): 186－194.

Mechanically induced strong red emission in samarium ions doped piezoelectric semiconductor CaZnOS for dynamic pressure sensing and imaging

Piezoelectric semiconductor with optical, electrical and mechanical multifunctions has great potential applications in future optoelectronic devices. The rich properties and applications mainly encompass the intrinsic structures and their coupling effects. Here, we report that lanthanide ions doped piezoelectric semiconductor CaZnOS:Sm3+ showing strong red emission induced by dynamic mechanical stress. Under moderate mechanical load, the doped piezoelectric semiconductor exhibits strong visible red emission to the naked eyes even under the day light. A flexible dynamic pressure sensor device is fabricated based on the prepared CaZnOS:Sm3+ powders. The mechanical-induced emission properties of the device are investigated by the optical fiber spectrometer. The linear characteristic emissions are attributed to the 4G5/2→6H5/2 (566nm), 4G5/2→6H7/2 (580–632nm), 4G5/2→6H9/2 (653–673nm) and 4G5/2→6H11/2 (712–735nm) f–f transitions of Sm3+ ions. The integral emission intensity is proportional to the value of applied pressure. By using the linear relationship between integrated emission intensity and the dynamic pressure, the real-time pressure distribution is visualized and recorded. Our results highlight that the incorporation of lanthanide luminescent ions into piezoelectric semiconductors as smart materials could be applied into the flexible mechanical-optical sensor device without additional auxiliary power, which has great potential for promising applications such as mapping of personalized handwriting, smart display, and human machine interface.

Wireless Data Acquisition of Transient Signals for Mobile Spectrometry Applications.

Wireless data acquisition using smartphones or handhelds offers increased mobility, it provides reduced size and weight, it has low electrical power requirements, and (in some cases) it has an ability to access the internet. Thus, it is well suited for mobile spectrometry applications using miniaturized, field-portable spectrometers, or detectors for chemical analysis in the field (i.e., on-site). There are four main wireless communications standards that can be used for wireless data acquisition, namely ZigBee, Bluetooth, Wi-Fi, and UWB (ultra-wide band). These are briefly reviewed and are evaluated for applicability to data acquisition of transient signals (i.e., time-domain) in the field (i.e., on-site) from a miniaturized, field-portable photomultiplier tube detector and from a photodiode array detector installed in a miniaturized, field-portable fiber optic spectrometer. These are two of the most widely used detectors for optical measurements in the ultraviolet-visible range of the spectrum. A miniaturized, 3D-printed, battery-operated microplasma-on-a-chip was used for generation of transient optical emission signals. Elemental analysis from liquid microsamples, a microplasma, and a handheld or a smartphone will be used as examples. Development and potential applicability of wireless data acquisition of transient optical emission signals for taking part of the lab to the sample types of mobile, field-portable spectrometry applications will be discussed. The examples presented are drawn from past and ongoing work in the authors' laboratory. A handheld or a smartphone were used as the mobile computing devices of choice.

English

English

Upconversion-luminescent/magnetic dual-functional sub-20 nm core-shell SrF2:Yb,Tm@CaF2:Gd heteronanoparticles.

Sub-20 nm core-shell and water-soluble SrF2:Yb,Tm@CaF2:Gd heteronanoparticles with both upconversion luminescence (UCL) and magnetic resonance imaging (MRI) capabilities were designed and synthesized via a two-step hydrothermal method. In the design of the heteronanoparticles, SrF2:Yb,Tm nanoparticles with high UCL efficiency are chosen as the core material for strong UCL output; and by epitaxially coating the SrF2:Yb,Tm core particles with inert and biocompatible shells of CaF2:Gd, the core-shell heteronanoparticles are endowed with a magnetic capability (longitudinal relaxivity of 2.4 mM(-1) s(-1)) for MRI, as well as an enhancement of the near infrared (NIR) UCL by 9.2 times. The aqueous dispersion of SrF2:Yb,Tm@CaF2:Gd heteronanoparticles with a concentration of 2.6 wt% can emit NIR UCL so as to be easily detected with a fiber optical spectrometer under illumination of a 975 nm laser diode with a power density of 8.8 W cm(-2). Such a dispersion with a Gd(3+) concentration of 0.0143 mM in the shell region of the heteronanoparticles can also generate the detectable quickening of longitudinal relaxation. The results promise the strong potential of this nanomaterial for applications in bioimaging as a dual-functional probe.

Rapid and label-free detection of ochratoxin A and aflatoxin B1 using an optical portable instrument

In this study, we report a novel assay for the combined on site detection of aflatoxin B1 (AFB1) and ochratoxin A (OTA), through a colorimetric biosensing system for AFB1 and a fluorimetric detection for OTA, exploiting the capability of the portable fibre optic spectrometer to perform both analyses. AFB1 was detected using the acetylcholinesterase (AChE) enzyme that is inhibited by this toxin, and the degree of inhibition was quantified by the Ellman's spectrophotometric method, obtaining a detection limit of 10µgL−1. OTA quantification was performed by monitoring its intrinsic fluorescence in methanol, reaching a detection limit of 0.1µgL−1. In order to successfully apply the analytical tool in the food analysis, immunoaffinity columns were used. Clean-up and quantification of both AFB1 and OTA in millet samples was obtained by HPLC-dedicated AflaOchra-Test HPLC™ (Vicam™) and Afla-OtaCLEAN™ (LC-Tech) immunoaffinity columns, followed by absorption/fluorescence detection. Millet samples which were fortified with both OTA (50µgkg−1) and AFB1 (20µgkg−1), gave recovery values of 100±6% for OTA, and 110±10% for AFB1, using AflaOchra-Test HPLC™. Single OTA clean-up and quantification in wine samples was obtained, using an OchraTest immunoaffinity column (Vicam™), reaching a detection limit of 0.3µgL−1 and recovery values between 80% and 120%.These results demonstrated the possibility of employing a single clean-up and a cost-effective, and easy to use analytical system for both AFB1 and OTA detection at µgkg−1 (ppb) level. Furthermore, in the case of positive samples, they could be analysed further, using standard chromatographic procedures, without any additional clean-up step, since the same extraction procedure of standard method is proposed in our method.

A fast, sensitive and stable fluorescent fiber-optic chemosensor for quantitative detection of Fe3+ in real water and HepG2 living cells

Based on the fluorescence quenching mechanism of Fe3+ to moxifloxacin (MOX), a fluorescence probe has been found and exhibits high sensitivity, unique selectivity and good stability toward Fe3+. Moreover, the MOX probe can rapidly response to the change of Fe3+ concentration in pure aqueous solution. The MOX probe was utilized for quantitative determination of Fe3+ in real water sample, showing a good linear relationship (R=0.9980) between (F0–F) and [Fe3+]1/2 at the Fe3+ concentration from 0.05–15μM. The detection limit was found to be 0.032μM, which is much lower than that of most literature reported. Furthermore, by merging the MOX probe and a Y-tape fiber-optic spectrometer, a fluorescent fiber-optic chemosensor has been developed to quantitatively monitor Fe3+ in HepG2 living cells in vivo. The monitoring results are consistence with that obtained from the confocal imaging technique. The established method possesses the advantages of fast responsive, high sensitivity, unique selectivity, very stability and good repeatability for quantitative monitoring Fe3+ in real water and HepG2 living cells. In addition, the complex mechanism of MOX toward Fe3+ has also been explored by Fourier transform infrared spectroscopy (FT-IR) and mass spectra (MS) in the present work.

Evanescent wave absorbance based U-bent fiber probe for immunobiosensor with gold nanoparticle labels

This study demonstrates a simple evanescent wave absorbance based sensing scheme for plasmonic sandwich immunoassay with the help of U-bent fiber probes as transducers. High absorbance sensitivity of the U-bent probes (200μm core and 1.5mm bend diameter) is exploited for sensitive detection of a small number of gold nanoparticles (AuNP) labels bound to the probe for the first time. Using 13nm AuNP labels conjugated with recognition antibodies, picomolar detection limit (2pM or 0.3ng/ml) for human immunoglobulin (HIgG) is achieved. The absorbance sensitivity and dynamic range were 0.019 A530nm/log (ng/ml) and 1–105ng/ml respectively. Nonspecific adsorption (NSA) of labels is minimized to less than 2% by PEGylation. The ease in U-bent probe fabrication and simple optoelectronic instrumentation consisting of an LED and a fiber optic spectrometer could facilitate extensive use of U-bent probes for several biosensing applications.

Characterizing the output settings of dental curing lights

ObjectivesFor improved inter-study reproducibility and ultimately improved patient care, researchers and dentists need to know what electromagnetic radiation (light) is emitted from the light-curing unit (LCU) they are using and what is received by the resin. This information cannot be obtained from a dental radiometer, even though many studies have used a dental radiometer. MethodsThe light outputs from six LCUs (two QTH and four broad-spectrum LED units) were collected in real-time using an integrating sphere connected to a fiberoptic spectrometer during different light exposures. ResultsIt was found that the spectral emissions were unique to each LCU, and there was no standardization in what was emitted on the various ramp (soft-start) settings. Relative to the normal use setting, using the ramp setting reduced the radiant energy (J) delivered from each LCU. For one of the four broad-spectrum LED LCUs, the spectral emissions in the violet range did not increase when the overall radiant power output was increased. In addition, this broad-spectrum LED LCU emitted no light from the violet LED chip for the first 5s and only emitted violet light when the ramp phase finished. ConclusionsA single irradiance value derived from a dental radiometer or from a laboratory grade power meter cannot adequately describe the output from the LCU. Manufacturers should provide more information about the light output from their LCUs. Ideally, future assessments and research publications that include resin photopolymerization should report the spectral radiant power delivered from the LCU throughout the entire exposure cycle.

Influence of Ambient Gas on Laser-Induced Breakdown Spectroscopy of Uranium Metal

Laser-induced breakdown spectroscopy (LIBS) is regarded as a suitable method for the remote analysis of materials in any phase, even in an environment with high radiation levels. In the present work we used the third harmonic pulse of a Nd:YAG laser for ablation of uranium metal and measured the plasma emission with a fiber-optic spectrometer. The LIBS spectra of uranium metal and their features in different ambient gases (i.e., argon, neon, oxygen, and nitrogen) at atmospheric pressure were studied. Strong continuum spectrum and several hundreds of emission lines from UI and UII were observed. It is found that the continuum spectrum observed in uranium not only comes from bremsstrahlung emission but is also due to the complex spectrum of uranium. The influence of ambient gas and the gas flow rate for ablation of uranium metal was investigated. The experimental results indicate that the intensity of the uranium lines was enhanced in argon and nitrogen. However, the intensity of uranium lines was decreased in oxygen due to the generation of UO and other oxides. The results also showed that the highest intensity of uranium lines were obtained in argon gas with a gas flow rate above 2.5 L/min. The enhanced mechanism in ambient gas and the influence of the gas flow rate were analyzed in this work.

Multicommuted flow injection method for fast photometric determination of phenolic compounds in commercial virgin olive oil samples

A multicommuted flow injection method has been developed for the determination of phenolic species in virgin olive oil samples. The method is based on the inhibitory effect of antioxidants on a stable and colored radical cation formation from the colorless compound N,N-dimethyl-p-phenylenediamine (DMPD•+) in acidic medium in the presence of Fe(III) as oxidant. The signal inhibition by phenolic species and other antioxidants is proportional to their concentration in the olive oil sample. Absorbance was recorded at 515nm by means of a modular fiber optic spectrometer. Oleuropein was used as the standard for phenols determination and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox) was the reference standard used for total antioxidant content calculation. Linear response was observed within the range of 250–1000mg/kg oleuropein, which was in accordance with phenolic contents observed in commercial extra virgin olive oil in the present study. Fast and low-volume liquid–liquid extraction of the samples using 60% MeOH was made previous to their insertion in the flow multicommuted system. The five three-way solenoid valves used for multicommuted liquid handling were controlled by a homemade electronic interface and Java-written software. The proposed approach was applied to different commercial extra virgin olive oil samples and the results were consistent with those obtained by the Folin Ciocalteu (FC) method. Total time for the sample preparation and the analysis required in the present approach can be drastically reduced: the throughput of the present analysis is 8 samples/h in contrast to 1sample/h of the conventional FC method. The present method is easy to implement in routine analysis and can be regarded as a feasible alternative to FC method.

Surface wetting of superhydrophobic aluminum oxide nanostructures investigated using the fiber-optic spectrometer and quartz crystal microbalance

We synthesized an anodic aluminum oxide nanostructure with a pore diameter of 80nm (AAO80) directly on a quartz crystal substrate and deposited a thin gold film onto the AAO80 (Au/AAO80). The nanostructure surfaces were rendered hydrophobic via different chemical modifications to yield partially or fully superhydrophobic surfaces; only the top gold surface was hydrophobic (T-Au/AAO), or both the gold and AAO surfaces were hydrophobic (TS-Au/AAO). The surface wetting properties of each nanostructure-grown quartz substrate immersed in water were investigated using a novel integrated system consisting of a fiber optic spectrometer and a quartz crystal microresonator (QCM). A QCM was used to measure the changes in the dissipation factor and the resonance frequency during surface wetting. A fiber optic UV–vis spectrometer was used to measure the changes in the wavelength and peak intensities of the interference fringes. Synchronous QCM and spectrometer measurements permitted in situ discrimination between the permeation of water into the nanopores and the replacement of air interlayer with water for the first time to the best of our knowledge.