Rhodamine 6G Solution Research Articles

Dendritic copper nanostructures for ultrasensitive detection of rhodamine 6G and Congo red

Surface-Enhanced Raman Scattering (SERS) is a fast-responding and non-destructive ultra-sensitive detection technique that can replace traditional chromatographic and spectroscopic analysis techniques. In this experiment, dendritic copper nanostructures were prepared by the solid-state ionics method and the vacuum hot evaporation process with an applied current of I=9μA. Using them as a SERS substrate, Raman detection was performed on the dye molecules Rhodamine 6G (R6G) and Congo Red (CR) to determine SERS enhancement performance. It is found that the growth of the prepared copper nanostructures has a top-end dominant phenomenon. The fractal dimension of the copper nanostructure was calculated using fractal theory, and it was revealed to be 1.560. Scanning electron microscopy (SEM) results showed that a large number of 60-80 nm regularly arranged copper nanoparticles were attached to the surface of the dendritic copper nanostructure. This is beneficial to increase the surface roughness of the substrate and improve the detection level of dye molecules. Subsequently, copper nanostructures can sensitively detect R6G and CR solutions as low as 1×10-13 mol/L and 1×10-7 mol/L, reaching single-molecule levels. The Raman mapping experiment showed that the mean relative standard deviation (RSD) values of R6G and CR were 12.3% and 12.9%, indicating high uniformity and reproducibility of the structure. This structure effectively achieves the fusion of uniformity, repeatability, and sensitivity, and shows broad application prospects in food detection.

Femtosecond laser fabrication of nanopillar arrays for Surface-Enhanced Raman scattering substrates

This work presents a femtosecond laser fabrication method for precision-engineered nanopillar arrays, applicable for surface-enhanced Raman scattering (SERS) substrates. The proposed method consists of two steps: (1) fabrication of nanopillar arrays using femtosecond laser-induced two-photon polymerization (TPP) technology; and (2) deposition of Ag nanoparticles on the fabricated nanopillar arrays. Nanopillar arrays of the proposed SERS substrates are optimized with geometrical parameters of diameter, height, spacing, and arrangement. A limit of detection (LOD) down to 10-7 mol/L for Rhodamine 6G solution is achieved and the enhancement factor is estimated to be up to 2 × 103. The experimental results indicate that the proposed SERS substrates have potential applications in biomedical detection, food safety monitoring, and quality control.

Ultra-low threshold pH sensor based on a whispering gallery mode microbubble resonator

Laser sensing has a wide range of applications. In this paper, we propose a pH sensing laser with an ultra-low threshold and low sample consumption based on a whispering-gallery-mode microbubble resonator. Rhodamine 6G aqueous solutions with different pH values are injected through microfluidic channels as the lasing gain media and interact with a high-quality factor microbubble cavity with a sample consumption of only 550 pL to achieve lasing. Subtle pH changes of the aqueous solution lead to changes in lasing intensity in real time, and the threshold reaches a minimum of 0.091 μ J/mm2. The low pump energy density effectively avoids the self-aggregation and photobleaching effects of dye molecules present in high-concentration rhodamine 6G solutions. The lasing characteristics under different pH conditions were determined experimentally and theoretically, and the results are in good agreement. Due to the deprotonation of amino groups in highly alkaline environments, the lasing threshold is highly dependent on the pH of rhodamine 6G aqueous solutions. In the pH range of 10.16–13.14, the lasing intensity changes considerably with the increasing pH. The proposed pH-sensing laser exhibits a fast response time, low toxicity, and a high signal-to-noise ratio, making it promising for highly sensitive alkaline detection in biological applications.

Reviewing the effect of aggregates in Rhodamine 6G aqueous solution on fluorescence quantum efficiency

Rhodamines constitute a class of dyes extensively investigated and applied in various contexts, primarily attributed to their high luminescence quantum yield. This study delves into the impact of aggregation on the thermal and optical properties of Rhodamine 6G (R-6G) solutions in distilled water. Examined properties encompass thermal diffusivity (D), temperature coefficient of the refractive index (dn/dT), fluorescence quantum efficiency (η), and energy transfer (ET). These parameters were assessed through thermal lens (TL) and conventional absorption and emission spectroscopic techniques. The dimerization of R-6G solutions was revisited, revealing that an increase in R-6G concentration alters the features of absorption and emission spectra due to dimer formation, resulting in unexpected behavior of η. Consequently, we introduce a novel model for the fraction of absorbed energy converted into heat (φ), which accounts for emissions from both monomers and dimers. Employing this model, we investigate and discuss the concentration-dependent behaviors of η for monomers (ηm) and dimers (ηd). Notably, our findings demonstrate that ηm values necessitate ηd = 0.2, a relatively substantial value that cannot be disregarded. Additionally, applying the Förster theory for dipole–dipole electric ET, we calculate microparameters for ET between monomers (CDD) and monomer–dimer (CDA). Critical ranges for ET in each case are quantified. Microparameter analysis indicates that ET between monomer–monomer and monomer–dimer species of R-6G dissolved in distilled water holds significance, particularly in determining ηm. These results bear significance, especially in scenarios involving high dye concentrations. While applicable to R-6G in water, similar assessments in other media featuring aggregates are encouraged.

Photon counting Raman spectroscopy: a benchmarking study vs surface plasmon enhancement

We demonstrate a single-photon counting Raman spectroscope and benchmark it against conventional and surface-enhanced Raman spectroscopy. For direct comparison without ambiguity, we use the same solutions of Rhodamine 6G and a common optical setup with either a spectrometer or an acousto-optic tunable filter, whereas the surface enhancement is realized with immobilized Ag nanoparticles. Our results find that the single photon counting significantly elevates the detection sensitivity by up to eight orders of magnitude, arriving at a comparable level of surface-enhanced Raman spectroscopy. Another significant advantage is with the time-resolving measurement, where we demonstrate time-gated and time-correlated single-photon counting with sub-nanosecond resolution. It offers insights into the samples’ transient responses and enables the isolation of Raman scattering from fluorescence signals.

Spontaneously formed dense Cu nanoislands and superior SERS properties of Cu nanoislands/Cu-Ta-Mo films

The co-sputtering method was utilized for preparing Cu-Ta-Mo films. The results indicate that the micromorphology of Cu-Ta-Mo films depends on the composition and annealing temperature. It is worth that the deposited Cu-Ta-Mo films surface was without nanoislands, and substantial quantities of Cu nanoislands are self-formed on the film's surface after annealing. The analysis indicates that the main reason for the Cu nanoislands formation is phase separation, due to atomic diffusion. Notably, the Cu grains in Ta-Cu-Mo films are surrounded by Ta- and Mo-rich amorphous areas, inhibiting the Cu grains’ growth and leading to the formation of nanoislands. In addition, annealing could promote atomic diffusion, thus facilitating Cu nanoislands’ formation and growth. The size and quantity of nanoislands influence the surface-enhanced Raman scattering (SERS) properties of Cu-Ta-Mo films. Furthermore, covering 10 nm Ag film on Cu nanoislands/Cu-Ta-Mo films’ surface could significantly enhance the SERS property, attributed to a synergistic enhancement of the electric field between Ag film and Cu nanoislands. The Ag film/Cu nanoislands/ Cu-16.34 at% Ta-13.05 at% Mo film applied to SERS substrate has high stability and sensitivity, and the limiting concentration for detecting the Raman characteristic spectra of Rhodamine 6G (R6G) solution can reach 5 × 10−14 M.

Unraveling the influence of solvent composition on Drop-on-Demand binder jet 3D printed tablets containing calcium sulfate hemihydrate

Recently, binder jet printed modular tablets were loaded with three anti-viral drugs via Drop on Demand (DoD) technology where drug solutions prepared in ethanol showed faster release than those prepared in water. During printing, water is used as a binding agent, whereas ethanol is added to maintain the porous structure of the tablets. Thus, the hypothesis is that the porosity would be controlled by manipulating the percentage of water and ethanol. In this study, Rhodamine 6G (R6G) was selected as a model drug due to its high solubility in water and ethanol, visualization function as a fluorescent dye, and potential therapeutic effects for cancer treatment. Approximately, 10 mg/ml R6G solutions were prepared with five different water–ethanol ratios (0–100, 75–25, 50–50, 75–25, 100–0). The ink solutions were printed onto blank binder jet 3D-printed tablets containing calcium sulphate hemihydrate using DoD technology. The tablets were dried at room temperature and then characterized using SEM-EDX, fluorescent microscope, TGA, XRD, FTIR, and DSC as well as in vitro release studies to investigate the impact of water–ethanol ratio on the release profile of R6G. Results indicated that the solution with higher ethanol ratio penetrated the tablets faster than the lower ethanol ratio, while the solution prepared with pure water was first accumulated onto the tablets' surface and then absorbed by the tablets. Moreover, tablets with more water content gained more weight and thickness. The EDX analysis and fluorescent microscope showed the uniform surface distribution of the drug. The SEM images revealed the difference in the tablet surface among the five formulations. Furthermore, the TGA data presents a notable increase in water loss, with XRD analysis suggesting the formation of gypsum in tablets containing elevated water content. The release study exhibited that the fastest release was from WE0-100, whereas the release rate decreases as the content of water increases. The WE0-100 releases more than 40 % drug within the first hour which is almost twice as high of the WE100-0 formulation. This DoD technology could distribute drugs onto the tablet's surface uniformly. The calcium sulfate would transform from hemihydrate to dihydrate form in the presence of water and therefore, those tablets treated with higher water content led to slower release. In conclusion, this study underscores the substantial impact of the water–ethanol ratio on drug release from binder jet printed tablets and highlights the potential of DoD technology for uniform drug distribution and controlled release.

Cost-effective efficient materials for dye degradation using non-aqueous sol-gel route.

In the present studies, the synthesis of pure ZnO nanoparticles and Mg and S-doped ZnO particles were carried out using a non-aqueous sol-gel method. The synthesized nanoparticles (NPs) are characterized using XRD, FESEM, EDX, FTIR, UV-Vis-DRS, XPS, PL, and BET surface area analysis. X-ray diffraction (XRD) techniques were used to examine the crystallization of ZnO, Mg-ZnO, and S-ZnO samples. The Mg-ZnO and S-ZnO samples exhibit significant c-axis compression and smaller crystallite sizes as compared to undoped ZnO. The optical band gap of Mg-ZnO and S-ZnO NPs were found to be 2.93eV and 2.32eV, respectively, which are lower than that of ZnO NPs (3.05eV). The S-doped ZnO resulted in the homogenous distribution of sulfur ions in the ZnO lattice crystal. XPS analysis revealed that the doped S element was mostly S4+ and S6+. A systematic evaluation has been conducted to assess the influence of several operational parameters, including doped/undoped stoichiometry, solution pH, catalyst dosage, and radical trapping experiment, on the photocatalytic degradation of Rhodamine 6G (Rh 6G) dye. Furthermore, we investigated the photocatalytic degradation activity of ZnO, Mg-ZnO, and S-ZnO samples with aquoues solution of 5ppm Rhodamine 6G (Rh 6G) at room temperature. Results indicated that pure ZnO nanoparticles have the highest photocatalytic degradation rate constant (0.00344min-1), compared to the samples Mg-ZnO (0.00104min-1) and S-ZnO (0.00108min-1) with Rh 6G dye in presence of visible light emitting diode (Vis-LED) source at room temperature. The enhanced visible light photocatalytic activities of pure ZnO NPs were attributed to their superior surface properties (18.30 m2/g) and effective electron-hole separation.

Synergistic enhancement of Ag layer and Cu particles on SERS property of spontaneously formed Cu nanoparticles/Ta–Cu alloy thin films

Surface-enhanced Raman scattering (SERS) is a highly accurate and ultra-sensitive single-molecule detection technology. Ta–Cu alloy thin films were prepared by co-sputtering technique at room temperature. The results have shown that as-deposited state Ta–Cu alloy thin films' surface was smooth, however, large amounts of Cu nanoparticles (NPs) were spontaneously formed on annealed alloy thin films' surface. Analysis indicated that the Ta-rich amorphous regions dispersed around Cu grains in Ta–Cu alloy thin films inhibited the growth of Cu grains and promoted the self-formation of nanoparticles on films' surface. The microscopic morphology of Ta–Cu alloy thin films can be regulated by varying the Cu content, film thickness, and annealing temperature. In addition, a 12 nm Ag covering layer on Cu NPs/Ta–Cu alloy thin films’ surface could improve SERS performance by synergistic enhancement of the electric field induced by the plasmon resonance of Cu NPs and reducing the spacing between Cu NPs to enhance the local electric fields. As SERS substrates, the Ag layer/Cu NPs/Ta–Cu alloy thin films can detect the Raman characteristic spectrum of 5 × 10−12 mol L−1 (M) rhodamine 6G (R6G) solution. This paper proposes an economical and environmentally friendly method to prepare low-cost and highly sensitive SERS substrates.

The Effects of Thermal Annealing and Postirradiation on Silver Nanoparticle Films Fabricated by Pulsed Laser Deposition in the Flowless Open Air

Herein, Ag nanoparticle (NP) films are fabricated by pulsed laser deposition technique in the flowless atmospheric air. A Q‐switched Nd:YAG pulsed laser beam is used for the ablation process. The fabricated NP films are postirradiated by the pulsed laser beam. In addition, as‐deposited NP films are annealed in argon gas flow ambient for 45 min at different temperatures (250, 350, and 450 °C), and also annealed at 450 °C for 15, 30, and 45 min. The characteristics of fabricated NP films are investigated after postirradiating by pulsed laser beam, and thermal annealing in Ar gas flow. UV–vis absorption spectroscopy is utilized to provide surface plasmon resonance (SPR) characteristics of films. The results show that thermal annealing can lead to strong enhancement, and also narrowing of the SPR spectrum. The results of field emission scanning electron microscopy and atomic force microscopy show that the annealing and postirradiation processes can influence the NPs size and film structure. As an application, the fabricated film is utilized for surface‐enhanced Raman spectroscopy (SERS) using a 10−6 molar aqueous solution of Rhodamine 6G. The SERS results indicate that the annealed NP films become more sensitive than the as‐deposited films.

Tin sulfides and cadmium sulfide mixture in montmorillonite with enhanced visible-light photocatalytic activity

In situ formation of tin sulfide (SnS) and cadmium sulfide (CdS) mixture in montmorillonite was carried out by the reaction between an aqueous dispersion of Sn2+- and Cd2+-montmorillonite and an aqueous solution of S2− (from Na2S). The effects of Sn2+ / Cd2+ molar ratios were examined. The appearance of two diffraction peaks (d001 = 1.3 and 1.4 nm) and/or the large mismatch (8%) of SnS and CdS lattices were attributed to the possible formation of SnS and CdS in two different interlayer spaces (segregation) of montmorillonite. The blue shifts of the absorption onset relating to the expansion of band gap energy, and the emission band as well as the increase of emission intensity of the intercalated SnS and CdS mixture were observed with increasing SnS / CdS molar ratio. The photodegradation of rhodamine 6G solution was achieved within 360 min by using the product, which has the molar ratio of Sn / Cd = 3:1. The photocatalytic process followed pseudo-first-order kinetic with a rate constant of 0.011 min−1. The scavenger test indicated that superoxide radical (O2•-) was the predominant species involved in the photocatalytic process. This result represented an important role of montmorillonite and the heterostructures of SnS and CdS in tailoring the photocatalytic properties.

Stretchable and Flexible Micro-Nano Substrates for SERS Detection of Organic Dyes.

Surface-enhanced Raman spectroscopy (SERS) is a precise and noninvasive analytical technique to identify vibrational fingerprints of trace analytes with sensitivity down to the single-molecule level. However, substrates can influence this capability, and current SERS techniques lack uniform, reproducible, and stable substrates to control plasma hot spots over a wide spectral range. Herein, we demonstrate a flexible SERS substrate via longitudinal stretching of a polydimethylsiloxane (PDMS) film. This substrate, after stretching and shrinking, exhibits an irregular wrinkled structure with abundant gaps and grooves that function as hot spots, thereby improving the hydrophobic properties of the material. To investigate the enhancement effect of Raman signals, silver nanoparticles (AgNPs) were mixed with Rhodamine 6G (R6G) solution, and the obtained blend was dropped onto the PDMS film to form a coffee ring pattern. According to the results, the hydrophobicity of the substrate increases with the degree of PDMS stretching, achieving the optimal level at 150% stretching. Moreover, the increase in hydrophobicity makes the measured molecules more aggregated, which enhances the Raman signal. The stretching and shrinkage of the PDMS film lead to a much higher density of nanogaps among nanoparticles and nanogrooves, which serve as multiple hot spots. Being highly localized regions of intense local fields, these hot spots make a significant contribution to SERS performance, improving the sensitivity and reproducibility of the method. In particular, the relative standard deviation (RSD) was found to be 2.5544%, and the detection limit was 1 × 10-7 M. Therefore, SERS using stretchable and flexible micro-nano substrates is a promising way for detecting dyes in wastewater.

Rhodamine-Conjugated Anti-Stokes Gold Nanoparticles with Higher ROS Quantum Yield as Theranostic Probe to Arrest Cancer and MDR Bacteria.

Photodynamic therapy (PDT) has recently become significant as a clinical modality for cancer therapy and multidrug-resistant (MDR) infections, replacing conventional chemotherapy and radiation therapy protocols. PDT involves the excitation of certain nontoxic molecules called photosensitizers (PS), applying a specific wavelength of light to generate reactive oxygen species (ROS) to treat cancer cells and other pathogens. Rhodamine 6G (R6G) is a well-known laser dye with poor aqueous solubility, and lower sensitivity poses an issue in using PS for PDT. Nanocarrier systems are needed to deliver R6G to cancer targets since PDT requires a higher accumulation of PS. It was found that R6G-conjugated gold nanoparticles (AuNP) have a higher ROS quantum yield of 0.92 compared to 0.3 in an aqueous R6G solution, increasing their potency as PS. Cytotoxicity assessment on A549 cells and antibacterial assay on MDR Pseudomonas aeruginosa collected from a sewage treatment plant are the evidence to support efficient PDT. In addition to their enhanced quantum yields, the decorated particles are effective in generating fluorescent signals that can be used for cellular imaging and real-time optical imaging, and the presence of AuNP is a valuable addition to CT imaging. Furthermore, the fabricated particle exhibits anti-Stokes properties, which makes it suitable for use as a background-free biological imaging agent. As a result, R6G-conjugated AuNP is an effective theranostic agent that prevents the progression of cancer and MDR bacteria, along with contrasting abilities in medical imaging with minimal toxicity observed in in vitro and in vivo assays using zebrafish embryos.

Microstructure Evolution of Ag/Ta Nanostructured Films for Surface-Enhanced Raman Scattering Substrates

Surface-enhanced Raman scattering (SERS), a nondestructive, ultrasensitive detection method, has a wide range of potential applications. However, its application is limited due to the weak Raman scattering signals. Therefore, it is urgent to explore a simple physical method to prepare SERS substrates with high detection limits and excellent reproducibility. In this work, Ta–Ag alloy films were prepared by magnetron sputtering at room temperature, and a large number of Ag nanoparticles were self-formed on the alloy films’ surface by adjusting the deposition time, Ag content, and annealing temperature. Further research reveals that this is because the amorphous Ta in the alloy films prevents the growth of Ag grains inside Ta–Ag alloy films, resulting in the diffusion of Ag atoms to the alloy film’s surface to form Ag nanoparticles. The results demonstrate that Ag nanoparticles/Ta 55.5 at % Ag alloy films used as SERS substrates have excellent reproducibility and high sensitivity to detect 5 × 10–16 mol L–1 rhodamine 6G (R6G) solution and 5 × 10–12 mol L–1 crystal violet (CV) solution. This method provides a simple approach to developing high-performance SERS substrates.

Mass producible, robust SERS substrates based on metal film on nanosphere (MFON) on an adhesive substrate for detection of surface-adsorbed molecules and their evaluation by helium ion microscopy.

We have developed a SERS stamp that can be pressed directly onto a solid surface for characterization of surface-adsorbed target molecules. The stamp was fabricated by transfer of a dense monolayer of SiO2 nanospheres from a glass surface onto a piece of adhesive tape and subsequent evaporation of silver. The performance of the resulting SERS stamps was evaluated by their exposure to methyl mercaptan vapor, and immersion in rhodamine 6G and ferbam solutions. It was found that beside the nanosphere diameter and metal deposition thickness, the extent of burial of the nanospheres into the adhesive tape, dictated by the pressure during the nanosphere transfer process, had a significant effect. We carried out FDTD calculations of the near field. Models are based on morphological information obtained from helium ion microscopy, which can provide high-resolution images of poor electrical conductors such as our SERS stamp. While one of our main eventual goals is detection of pesticides on agricultural produce, we have begun to take a careful step by testing our SERS stamp on better characterized surfaces such as a porous gel surface, having been immersed in fungicides such as ferbam. We also present our preliminary results with ferbam on oranges. It is expected that our well-characterized SERS stamp will play a role in shedding light on the poorly studied transfer process of target molecules onto a SERS surface as well as serving as a new SERS platform.

Emission Characteristics of the Side Radiation of Excited of the Layer of Alcohol Solution of Rhodamine 6G with the Round Geometric Shape

Emission Characteristics of the Side Radiation of Excited of the Layer of Alcohol Solution of Rhodamine 6G with the Round Geometric Shape

Electrically controllable self-assembly of gold nanorods into a plasmonic nanostructure for highly efficiency SERS.

In this Letter, a method for the rapid and efficient preparation of ultrasensitive detection substrates by assembling gold nanorod suspensions with the application of an alternating current (AC) field is proposed, and it is found that frequency and voltage are the effective means of regulation. A sandwich structure (parallel SiO2 plate) not only effectively slows down the evaporation rate, but also visually reveals the changes in the assembly process. Under the optimal assembly conditions, the sensitivity and uniformity of the substrate to different probe molecules are tested. The Raman detection results experimentally show that the detection limits of Rhodamine 6G (Rh6G), crystal violet (CV), and Aspartame (APM) molecular solutions are 10-14 M, 10-10 M, and 62.5 mg/L, respectively, and the mixed dye molecular solutions can also be effectively distinguished. Furthermore, Rh6G and CV characteristic peaks at 1647 cm-1 and 1619 cm-1 were measured at randomly selected positions, and their relative standard deviations (RSDs) were 5.63% and 8.45%, respectively, indicating that the substrate has good uniformity. The effective regulation of the self-assembly results of nanoparticles will further enhance the practical application effect of surface-enhanced Raman technology and expand the application prospects of this technology.

Accurate assessment of the effect of Rhodamine 6G solution as a spectral converter on biomass production of microalgae Chlorella sp., nitrate uptake, and energy consumption by the light source.

Spectral conversion of light introduced as a new technique to manage incoming light photons into the culture medium of photosynthetic microorganisms which can increase biomass production. In this work, a much more accurate value of the effect of spectral conversion on the growth of Chlorella sp. was obtained. For this purpose, the light source and Rhodamine 6G solution, as a spectral converter, was placed in the center of the culture flask, which was covered with aluminum foil. The loss of photons was largely avoided due to the additional homogeneous distribution of light. Modification of white light using the solution has increased biomass productivity up to 300%. Also, for biomass productivity of 1mg L-1day-1, the energy consumption of the white light source was reduced up to 75%. Nitrate uptake has also increased up to 28%, and intracellular lipid content has decreased, as well.

Accurate correction method and algorithm of fluorescence secondary inner filter effect (sIEF) in fluorescence quantitative analysis

Fluorescence spectroscopy is a reliable and widely used analytical method. The fluorescence inner filter effect (IFE) is one of the main obstacles in the application of fluorescence spectroscopy and an error source in fluorescence analysis, resulting in the fluorescence spectrum distortion, the spectral shape distortion, and the nonlinearity between fluorescence intensity and fluorophore concentration. An optimized parameter reflecting the self-absorption effect - the fluorescence attenuation absorption index of secondary inner filter effect (sIFE) nopt - is proposed in this paper. Considering the received fluorescence in a direction perpendicular to the incident light, it is related to the solute–solvent system of the fluorescent substance, neither the geometric parameters of the cuvette and the light beam nor the concentration of the fluorescent substance. nopt can accurately reflect the degree to which the fluorescence is affected by the sIFE and correct for any non-ideality of the shapes of excitation/emission beams. The principle and determination method of nopt are explained in detail. Accordingly, an algorithm for the fluorescence spectroscopic correction by nopt is designed. To verify the method, the fluorescence spectra and absorbance spectra of the solutions of fluorescein sodium, rhodamine B, rhodamine 6G, and chlorophyll-a with a series of concentration gradients were measured, respectively. The influence of solvent effect on sIFE correction was also studied. The experiments show that different solute–solvent systems of the fluorescent substances have their own nopt. The novel algorithm can determine the nopt, correct the intensity attenuation and the peak red-shift of the fluorescence spectrum caused by the sIFE, expand the linear range of the concentration predicted by the fluorescence intensity, reduce the error of the prediction model, and improve the measurement accuracy.

Fiber-coupled fluorescence light source suitable for spectroscopic applications

An experimental study of a fluorescent broadband light source fully compatible with optical fibers is presented in the article, with the aim of using it for excitation-emission matrix fluorescence spectroscopy. A fiber optic glass ferrule filled with a solution of Rhodamine 6G in glycerin was used for the basic construction of the light source. The ferrule is coupled with optical fibers to illuminate the dye medium and to receive the fluorescent signal. A tuning of the light spectrum from the source between 528 nm and 660 nm with a shift of 1 nm is achieved by means of a monochromator. Full Text: PDF ReferencesN. Hoinka and T. Fuhrmann-Lieker, "Amplified Spontaneous Emission in Paper", Sci. Rep. 9, 1 (2019), CrossRef J. Włodarski, M. Chychłowski, "Chemically tuned light source with an optical pump", Photonics Lett. Pol. 13(2), 46 (2021). CrossRef J. Żmojda, P. Miluski, M. Kochanowicz, J. Dorosz, A. Baranowska, M. Leśniak and D. Dorosz, "Luminescent properties of active optical fibers", Photonics Lett. Pol. 11(2), 50 (2019). CrossRef K. Jakubowski, W. Kerkemeyer, E. Perret, M. Heuberger, R. Hufenus, "Liquid-core polymer optical fibers for luminescent waveguide applications", Mater. Des. 196, 1 (2020). CrossRef V. Vladev, T. Eftimov, "Fiberized fluorescent dye microtubes", Proc. SPIE 8770, 87700V-1 (2013). CrossRef V. Vladev, T. Eftimov, W. Bock, "Broad-band fluorescent all-fiber source based on microstructured optical fibers", Photonics Lett. Pol., 7(2), 41 (2015). CrossRef V. Vladev, T. Eftimov, W. Bock, "Fluorescent all-fiber light source based on micro-capillaries and on microstructured optical fibers terminated with a microbulb", Opt. Comm. 356, 34 (2015). CrossRef V. Vladev, T. Eftimov, S. Nedev, "Excitation efficiency of a side-pumped fiberized fluorescent dye microcapillary", Opt. Fib. Tech. 28, 28 (2016). CrossRef V. Vladev, M. Todorova, V. Slavchev, M. Brazkova, E. Belina, S. Bozhkov, P. Radusheva, "A new basic structure suitable for a fully integrated all-fiber-optic stimulated emission dye source", J. Phys.: Conf. Ser. 1859 (012059), 1 (2021). CrossRef V. P. Vladev, M. M. Todorova, M. S. Brazkova, S. I. Bozhkov, "Diode-pumped all-fiber-optic liquid dye laser", Laser Phys. Lett. 18 (11), 115103 (2021), CrossRef G. Dyankov, T. A. Eftimov, N. Malinowski, E. Belina, H. Kisov, P. Mikulic, W. J. Bock, "A highly efficient biosensor based on MAPLE deposited hemoglobin on LPGs around phase matching turning point", Opt. Laser Technol. 123, 1 (2020). CrossRef T. Eftimov, G. Dyankov, A. Arapova, P. Kolev and V. Vladev, W4.73 , OFS-27, Optical Fiber Sensor Conference - 2022, 29 Aug- 2 Sept., The Westin Alexandria, Alexandria, Virginia, USA. CrossRef G. Rossi, J. Durek, S. Ojha, O. K. Schlüter, "Fluorescence-based characterisation of selected edible insect species: Excitation emission matrix (EEM) and parallel factor (PARAFAC) analysis", CRFS 4, 862 (2021). CrossRef L. Li, Y. Wang, W. Zhang, S. Yu, X. Wang, N. Gao, "New advances in fluorescence excitation-emission matrix spectroscopy for the characterization of dissolved organic matter in drinking water treatment: A review Author links open overlay panel", Chem. Eng. J. 381, 1 (2020). CrossRef