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Optical Characterization of Doped Thermoplastic and Thermosetting Polymer-Optical-Fibers
摘要： The emission properties of a graded-index thermoplastic polymer optical fiber and a step-index thermosetting one, both doped with rhodamine 6G, have been studied. The work includes a detailed analysis of the amplified spontaneous emission together with a study of the optical gains and losses of the fibers. The photostability of the emission of both types of fibers has also been investigated. Comparisons between the results of both doped polymer optical fibers are presented and discussed.
关键词： polymer optical fibers,thermoplastic fibers,rhodamine 6G,light-emitting polymers,optical gain,amplified spontaneous emission,thermosetting fibers
更新于2025-11-14 15:30:11
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H2 Gas Sensor Based on Pd/ZnO Nanostructures Deposited on Tapered Optical Fiber
摘要： A novel H2 sensor using tapered optical fiber coated with Pd/ZnO nanostructures have been developed. The ZnO nanostructures was synthesized and deposited onto tapered optical fiber via chemical bath deposition (CBD) method. The ZnO was characterized by FESEM, XRD and EDX to confirm the material properties. It was discovered that the sensor is sensitive towards different concentrations of H2 in synthetic air at 180oC of operating temperature. By varying the deposition time of ZnO coating, different thickness of ZnO layer can be obtained. It was observed that with 280 nm thickness, the maximum absorbance response can be achieved. Further investigation with sensor sample of as-prepared and annealed was carried out to study its sensing performance towards H2. The absorbance response of 280 nm thickness of annealed Pd/ZnO has increased 64% as compared to as-prepared Pd/ZnO upon 1% H2 exposure in the synthetic air when measured in the visible to near infra-red optical wavelength. It can be concluded that the Pd/ZnO optical fiber sensor with thickness around 280 nm provided better sensitivity in sensing H2 at 180oC as compared to other thicknesses investigated.
关键词： Optical sensors,zinc oxide,sensing material
更新于2025-11-14 15:30:11
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Optical and photocatalytic properties of bismuth vanadate doped bismuth silicate glasses
摘要： The aim of this research is to investigate optical and photocatalytic properties of 0.25, 0.5 and 1.0 mol% BiVO4 doped bismuth silicate glasses. The glasses composition is 60 mol% SiO2 and 40 mol% Bi2O3. Optical spectra and the analysis of color by CIELab system revealed that the addition of BiVO4 changed the color of the glasses from pale yellow to yellow-orange with the narrower band gap. Photocatalytic activity was observed in 0.5 and 1.0 mol% BiVO4-doped glass. The effect of BiVO4 doping to bismuth silicate glass is also discussed.
关键词： Optical,Photocatalysis,Bismuth vanadate,Bismuth silicate glass,CIELab
更新于2025-11-14 15:30:11
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Correlation of acetylene plasma discharge environment and the optical and electronic properties of the hydrogenated amorphous carbon films
摘要： Thin films from polymeric and graphitic hydrogenated amorphous carbon (a-C:H) were deposited over a glass substrate from acetylene (C2H2) plasma by using a conventional plasma enhanced chemical vapor deposition (PECVD). Radio frequency capacitively coupled plasma (RF CCP) source operating at a frequency of 13.56 MHz was used for generation of the discharge. Optical emission spectroscopy (OES) results showed strong optical emissions from diacetylene ion C4H2+ at a wavelength of 506 nm. The energy dispersive X-Ray (EDS) measurements illustrated that the carbon content in the deposited films increased with increasing of power. The Raman and IR results demonstrated that the films deposited at low bias voltages 340 V are so called polymeric a-C:H with high sp3 fraction and high hydrogen content, while the films deposited at high bias voltages 877 V are so called graphitic a-C:H with low sp3 fraction and low hydrogen content. Quantitative information were obtained from fitting the high asymmetrical vibrational modes of Raman and IR spectra by using Fano model expression together with Lorentzian function. The results presented here point out that there is a relation between the intensity of C4H2+ ion emissions and the deposited films properties.
关键词： Optical Emission,diacetylene ion,RF CCP,Hydrogenated amorphous carbon,FTIR,Raman spectroscopy
更新于2025-11-14 15:30:11
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Characterization of a non-contact imaging scintillator-based dosimetry system for total skin electron therapy
摘要： Surface dosimetry is required for ensuring effective administration of total skin electron therapy (TSET); however, its use is often reduced due to the time consuming and complex nature of acquisition. A new surface dose imaging technique was characterized in this study and found to provide accurate, rapid and remote measurement of surface doses without the need for post-exposure processing. Disc-shaped plastic scintillators (1 mm thick x 15 mm) were chosen as optimal-sized samples and designed to attach to a flat-faced phantom for irradiation using electron beams. Scintillator dosimeter response to radiation damage, dose rate, and temperature were studied. The effect of varying scintillator diameter and thickness on light output was evaluated. Furthermore, the scintillator emission spectra and impact of dosimeter thickness on surface dose were also quantified. Since the scintillators were custom-machined, dosimeter-to-dosimeter variation was tested. Scintillator surface dose measurements were compared to those obtained by optically stimulated luminescence dosimeters (OSLD). Light output from scintillator dosimeters evaluated in this study was insensitive to radiation damage, temperature, and dose rate. Maximum wavelength of emission was found to be 422 nm. Dose reported by scintillators was linearly related to that from OSLDs. Build-up from placement of scintillators and OSLDs had a similar effect on surface dose (3.9% increase). Variation among scintillator dosimeters was found to be 0.3 ± 0.2%. Scintillator light output increased linearly with dosimeter thickness (~1.9×/mm). All dosimeter diameters tested were able to accurately measure surface dose. Scintillator dosimeters can potentially improve surface dosimetry-associated workflow for TSET in the radiation oncology clinic. Since scintillator data output can be automatically recorded to a patient medical record, the chances of human error in reading out and recording surface dose are minimized.
关键词： non-contact,surface dosimetry,optical imaging,scintillator,remote
更新于2025-11-14 15:30:11
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Dynamically Optimized Multi-Interface Novel BiSI-Promoted Redox Sites Spatially Separated N-p-n Double Heterojunctions BiSI/MoS2/CdS for Hydrogen Evolution
摘要： Novel BiSI promoted n-p-n double heterojunctions multi-interface photocatalyst BiSI/MoS2/CdS was constructed. BiSI is applied to photocatalytic hydrogen evolution. It possesses a small band gap and a strong optical absorption coefficient, therefore, the optical absorption scope and coefficient of MoS2/CdS have been effectively enhanced by compounding with BiSI. The continuous heterojunctions strengthened the function of single junction and guided the carriers’ transfer direction, thus the redox reactions occur at spatially separated sites. Built-in electric field along the radial direction of BiSI nanorod and MoS2 interlayer helps to transport carriers within lifetime. Carrier dynamics is optimized by multi-interface structure. In general, a new material BiSI is introduced to construct a multi-interface structure to optimize carrier dynamics, which resulted in a 46-fold increase in hydrogen production efficiency.
关键词： multi-interface,dynamics optimization,enhanced optical absorption,photocatalytic water splitting,n-p-n continuous heterojunctions,BiSI
更新于2025-11-14 15:29:11
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Polycrystal Synthesis, Crystal Growth, Structure, and Optical Properties of AgGaGe <sub/><i> <i>n</i> </i> </sub> S <sub/> 2( <i> <i>n</i> </i> +1) </sub> ( <i>n</i> = 2, 3, 4, and 5) Single Crystals for Mid-IR Laser Applications
摘要： AgGaGenS2(n+1) crystal is a series of quaternary for mid-IR laser applications of nonlinear optical materials converting a 1.064 μm pump signal (Nd:YAG laser) to 4?11 μm laser output, but only AgGaGeS4 has attracted the most attention, remaining the other promising AgGaGenS2(n+1) crystal whose physicochemical properties can be modulated by n value. In this work, AgGaGenS2(n+1) (n = 2, 3, 4, and 5) polycrystals are synthesized by vapor transport and mechanical oscillation method with di?erent cooling processes. High-resolution X-ray di?raction analysis and re?nement have revealed that all the four compounds are crystallized in the noncentrosymmetric orthorhombic space group Fdd2, resulting in the excellent nonlinear optical property, and the distortion of tetrahedron with the variation of n value causes the discrepancy of physicochemical property. Besides, using the modi?ed Bridgman method, AgGaGenS2(n+1) single crystals with 15 mm diameter and 20?40 mm length have been grown. We have discussed the structure and composition of AgGaGenS2(n+1) by XPS spectra and analyzed the three kinds of vibration modes of tetrahedral clusters by the Raman spectra. The Hall measurement indicates that the AgGaGenS2(n+1) single crystals are p-type semiconductor, and the carrier concentration decreases with the increasing n value. All the transmittances of as-grown AgGaGenS2(n+1) samples exceeds 60% in the transparent range, especially the transmittance of AgGaGe2S6, is up to 70% at 1064 nm, and the band gap of as-grown crystal increases from 2.85 eV for AgGaGe2S6 to 2.92 eV for AgGaGe5S12. After a thermal annealing treatment, the absorptions at 2.9, 4, and 10 μm have been eliminated, and the band gap changed into the range of 2.89?2.96 eV.
关键词： Hall measurement,nonlinear optical materials,thermal annealing treatment,vapor transport,AgGaGenS2(n+1),Bridgman method,Raman spectra,mid-IR laser applications,XPS spectra,mechanical oscillation method
更新于2025-11-14 15:27:09
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The impact of ZnO configuration as an external layer on the sensitivity of a bi-layer coated polymer optical fiber probe
摘要： Salinity magnitude changes are a critical factor for determining the chemistry of natural water bodies and biological processes. Label-free refractive index sensors are promising devices for detecting these changes. A polymer optical fiber (POF) sensor modified with cladding treatment and a bi-layer zinc oxide/silver (ZnO/Ag) nanostructure coating to determine sodium chloride concentration changes through refractive index variations in water is experimentally demonstrated. The use of three ZnO nanostructure shapes, nanoparticles and horizontally and vertically oriented nanorods, as an external layer and a broad spectrum light source from the visible (Vis) to the near infrared (NIR) region are investigated to achieve optimum sensitivity. The rms roughness, optical band-gap and zeta potential (ZP) value for the vertically oriented sample are 148 nm, 3.19 eV and 5.96 mV, respectively. In the NIR region the wavelength–intensity sensitivity values of probes coated with ZnO nanoparticles and horizontally and vertically oriented nanorods are 104 nm RIU?1–12 dB RIU?1, 63 nm RIU?1–10 dB RIU?1 and 146 nm RIU?1–22 dB RIU?1, respectively, and in the Vis area the values are 65 nm RIU?1–14 dB RIU?1, 58 nm RIU?1–11 dB RIU?1 and 89 nm RIU?1–23 dB RIU?1, respectively. The maximum amplitude sensitivity is obtained for the probe coated with vertically aligned ZnO nanorods in the NIR area due to the deeper penetration of evanescent waves, a higher surface-volume ratio, better crystallinity, more adhesive interactions with salt molecules, larger surface roughness and higher-order dispersion compared to the other coated ZnO nanostructures.
关键词： sensitivity,salinity,nanorods,refractive index sensors,ZnO/Ag nanostructure,polymer optical fiber,nanoparticles
更新于2025-11-14 15:25:21
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Measurement of Optical Constants of TiN and TiN/Ti/TiN Multilayer Films for Microwave Kinetic Inductance Photon-Number-Resolving Detectors
摘要： We deposit thin titanium nitride (TiN) and TiN/Ti/TiN multilayer ?lms on sapphire substrates and measure the re?ectance and transmittance in the wavelength range from 400 to 2000 nm using a spectrophotometer. The optical constants (complex refractive indices), including the refractive index n and the extinction coef?cient k, have been derived. With the extracted refractive indices, we propose an optical stack structure using low-loss amorphous Si (a-Si) anti-re?ective coating and a backside aluminum (Al) re?ecting mirror, which can in theory achieve 100% photon absorption at 1550 nm. The proposed optical design shows great promise in enhancing the optical ef?ciency of TiN-based microwave kinetic inductance photon-number-resolving detectors.
关键词： TiN,Optical constants,Microwave kinetic inductance detectors,Refractive index
更新于2025-11-14 15:25:21
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Density functional theory for investigation of optical and spectroscopic properties of zinc-quinonoid complexes as semiconductor materials
摘要： Three Zn(II) complexes of a new organic compound [(E)-4-methyl-N1-((E)-4-methyl-6-(p-tolylimino) cyclohex-3-en-1-ylidene)-N2-(p-tolyl) benzene-1, 2-diamine] (HMBD) were prepared and characterized by various techniques, including Fourier transform infrared (FTIR), UV–visible measurements, 1H-NMR, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The data revealed that the HMBD ligand has an ONS tridentate-forming structure, while the complex of HMBD with zinc metal has a distorted octahedral structure, providing sp3d2 hybridization type. The geometry, HOMO, LUMO, polarizability, and other energetic parameters were evaluated by density functional theory (DFT) on Materials Studio package. Optical band gap (Eg) was estimated by DFT theory and optical properties for [Zn(MBD)(Cl)(H2O)2].2H2O (1), [Zn(MBD)](NO3)2H2O].2H2O (2), and [Zn(MBD)(CH3COO)(H2O)].3H2O (3) thin films as well, revealing that [Zn(MBD)(CH3COO)(H2O)].3H2O (3) thin film has the smallest energy gap and can be considered a highly efficient photovoltaic material. The resulting band gap energy values from both methods were found to be close to each other. Thin films of the ligand and zinc complexes were successfully fabricated by spin coating method. The optical constants, refractive index (n), and the absorption index (k) over the spectral range of the thin films were determined.
关键词： Optical properties,Semiconductor materials,Density functional theory,Thin film,Zinc-quinonoid complexes
更新于2025-11-14 15:19:41