- 标题
- 摘要
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- 实验方案
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Onlinef?hige Signalauswertung für spektraloptische Sensoren mit einer Doppelphotodiode / Online-capable signal processing for spectral-optical sensors using a double-layered photodiode
摘要： Spectral-optical sensor technology records physical as well as (bio-)chemical measurands on the basis of specific spectral property changes of the transducer. In this article a signal evaluation with a double-layered photodiode (DPD) is presented, which is a spectrally selective element and detector at the same time due to its stack structure of two different spectrally sensitive photodiode layers. Instead of extracting the spectral information from a spectrum, the centroid of the overall spectral distribution is evaluated in real time on the basis of the measured ratio of the two wavelength-dependent photocurrents. The performance of the DPD is demonstrated by means of surface temperature measurements with the phosophor NaYF4:Yb3+,Er3+. It is shown that with an integrator-based readout electronics a max. measurement deviation for the centroid wavelength of 0.1 nm can be achieved. In sum, the online-capable signal processing and compact size of the double-layered photodiode foster the on-site applicability of spectral-optical sensors for the process industry, environmental monitoring and many others fields.
关键词： thermometry,anorganic phosphors,optoelectronic interrogator,spectral-optical sensors,Double-layered photodiode
更新于2025-09-16 10:30:52
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Lithium ion doping triggered splendid quantum efficiency and thermal stability in Li <sub/>2</sub> SrSiO <sub/>4</sub> : <i>x</i> Eu <sup>2+</sup> phosphors for optical thermometry and high luminous efficiency white-LED
摘要： Eu2+/Li+-Codoped Li2SrSiO4 orange-yellow phosphors were developed for the applications of white light-emitting diodes (white-LEDs) and optical thermometry. Under near-ultraviolet and blue light excitation, the resultant phosphors exhibited the emissions of Eu2+ ions with an optimal doping concentration of 5 mol% and the concentration quenching mechanism was prevailed to be the dipole–quadrupole interaction. Through the incorporation of Li+ ions into the host lattices, the thermal stability and internal quantum efficiency of the synthesized phosphors were boosted. When the excitation wavelengths were 419 and 449 nm, the internal quantum efficiencies of the Eu2+/Li+-codoped Li2SrSiO4 phosphors were increased to 73% and 69%, respectively. The temperature dependent emission spectra were employed to characterize the thermal stability of the studied samples. The white-LED lamps utilizing the Eu2+/Li+-codoped Li2SrSiO4 phosphors as the orange-yellow component exhibited enhanced photoelectric properties. Furthermore, based on the temperature dependent bandwidth of Eu2+ ions, the thermometric performance of the resultant compounds was studied in detail and the maximum sensitivity was 0.049 K?1. The phosphors with multi-excitation wavelengths were suitable for high luminous efficiency white-LEDs and optical thermometers.
关键词： Li2SrSiO4,Eu2+/Li+-codoped,thermal stability,quantum efficiency,phosphors,white-LEDs,optical thermometry
更新于2025-09-16 10:30:52
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Metallic Nanomaterials (Part B) || 5. Size-controlled atomically precise copper nanoclusters: Synthetic protocols, spectroscopic properties and applications
摘要： Noble metal nanoclusters (NCs) are a new class of nanomaterials which are considered being a missing link between isolated metal atoms and metal nanoparticles (NPs). The sizes of the NCs are comparable to the Fermi wavelength of the conduction electrons, and this renders them to be luminescent in nature. They exhibit size-dependent fluorescence properties spanning almost the entire breath of the visible spectrum. Among all the noble metal NCs being explored, copper NCs (CuNCs) are the most rarely investigated primarily because of their propensity of getting oxidised. In this chapter, we have given a comprehensive understanding as to why these NCs are luminescent in nature. We have also given a detailed overview regarding the various templates used for the synthesis of these CuNCs along with the respective protocols being followed. The various instrumental techniques used to characterize these CuNCs are discussed which provides an in-depth understanding as to how these CuNCs can be properly examined. Finally, we have highlighted some of the most recent applications of these CuNCs which make them unique to serve as the next-generation fluorophores.
关键词： nano-thermometry,bio-imaging,sensing,synthetic protocols,instrumentations,spectroscopic properties,templates,luminescent nanoclusters
更新于2025-09-16 10:30:52
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On the application of a supercontinuum white light laser for simultaneous measurements of temperature and velocity fields using thermochromic liquid crystals
摘要： Simultaneous velocity and temperature measurements using thermochromic liquid crystals (TLC) as tracer particles are discussed, with regard to measuring range, uncertainty and spatial resolution. For the first time, a supercontinuum laser is used to illuminate these particles, which shall later be used for the characterization of the momentum and heat transfer in Rayleigh-Bénard cells with high aspect ratio using particle image velocimetry (PIV) and particle image thermometry (PIT). Light scattered from the TLCs is analyzed by spectrometer measurements, revealing its general scattering characteristics depending on the angle between the light sheet plane and the viewing axis. It is shown that white light sources with continuous spectral characteristic and a slightly higher fraction of light in the red wavelength range perform well, thereby the supercontinuum white light laser can be used, even though it has a cut-in wavelength of about 475 nm. The numerical aperture of the detection optics and chromatic aberrations of the laser light significantly affect the temperature sensitivity and dynamic range of the color of the TLCs. This may cause an effective temperature sensitivity range of about one-tenth of their nominal range, particularly at large angles between light sheet plane and viewing axis, as usually applied in PIV. A simultaneous velocity and temperature measurement in a Rayleigh-Bénard cell experimentally validates that the use of the supercontinuum laser allows for reliable simultaneous PIV and PIT measurements with high spatial resolution of less than 500 μm in out-of-plane direction, on condition that an appropriate two-dimensional calibration is applied.
关键词： Thermochromic liquid crystals,Supercontinuum laser,Rayleigh-Bénard convection,Particle image thermometry,Particle image velocimetry
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID) - Miramar Beach, FL, USA (2019.8.19-2019.8.21)] 2019 IEEE Research and Applications of Photonics in Defense Conference (RAPID) - Time-Resolved, Laser-Absorption Temperature Measurement in Shock Heated Mixtures with Reduced Beam Steering and Emission Noise
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关键词： optical diagnostics,spectroscopy,thermometry,shock tube
更新于2025-09-16 10:30:52
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Thermoplasmonic Maskless Lithography on Upconverting Nanocomposites Assisted by Gold Nanostars
摘要： Photothermal effects in plasmonic nanoparticles can be used to locally modify temperature-sensitive materials. Polylactic acid (PLA) is a thermoplastic biodegradable polymer with a glass transition temperature around 60 ?C that has been popularized as a feedstock material for 3D printing. Here, we extend its use to produce thin PLA films that can be modified at the microscopic level when covered with gold nanostars (AuNSs). The heat dissipation generated when exciting the plasmon resonance of AuNSs, under exposure to 976 nm focused laser light, produce an increase in the local temperature of more than 100 ?C. When the temperature surpasses the glass transition of the base PLA layer, AuNSs get attached to the polymer surface. The following dissolution of the unexposed material in acetone bath permits the precise control of the engraving process at the microscale. Furthermore, Er3+ doped upconverting nanoparticles embedded into the PLA layer can act as optical nanothermometers to probe the local temperature, simultaneously allowing the visualization of the laser spot. A computer numerical control (CNC) system was developed to drive the laser writing beam and transfer 2D patterns, opening up the thermoplasmonic maskless lithography technique. Suitable for rigid and flexible substrates coated with PLA, the methods and materials developed here were applied to produce patterned substrates for surface enhanced Raman spectroscopy, and luminescent optical encoding for anti-counterfeiting technologies.
关键词： photothermal nanoparticles,gold nanostars,optical thermometry,thermoplasmonics,maskless lithography,upconversion nanoparticles
更新于2025-09-16 10:30:52
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Investigation of Five Organic Dyes in Ethanol and Butanol for Two-Color Laser-Induced Fluorescence Ratio Thermometry
摘要： In this article, we compare absorption and temperature-dependent ?uorescence spectra of ?ve organic dyes for 2c-LIF (two-color laser-induced ?uorescence) thermometry in ethanol and butanol. The dyes ?uorescein, eosin Y, rhodamine B, rhodamine 6G, and sulforhodamine 101 individually mixed in ethanol and butanol were studied at liquid temperatures of 25–65 °C. The self-absorption spectral bands are analyzed along with intensity ratios and the respective sensitivities for one-dye and two-dye 2c-LIF thermometry are deduced. For one-dye 2c-LIF, rhodamine B showed the highest sensitivity of 2.93%/°C in ethanol and butanol, respectively. Sulforhodamine 101 and rhodamine 6G showed the least sensitivities of 0.51%/°C in ethanol and butanol, respectively. For two-dye 2c-LIF, rhodamine B/sulforhodamine 101 exhibited the highest temperature sensitivities of 2.39%/°C in ethanol and butanol, respectively. The dye pair eosin Y/sulforhodamine 101 showed the least sensitivities of 0.15%/°C and 0.27%/°C in ethanol and butanol, respectively.
关键词： biofuels,thermometry,laser-induced ?uorescence,sensitivity,solvents
更新于2025-09-12 10:27:22
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The effects of gold nanoparticles characteristics and laser irradiation conditions on spatiotemporal temperature pattern of an agar phantom: a simulation and MR thermometry study
摘要： In this paper, the effects of parameters related to gold nanoparticles (type, size, and concentration) and the laser parameters on spatiotemporal temperature pattern of an agar phantom during a photothermal therapy (PTT) procedure were modeled and then experimentally verified. Eight agar phantoms loaded by gold nanoparticles were made. An agar phantom without any nanoparticles was also considered as the control. Different sizes of two types of gold nanoparticles (spherical and silica-gold core shell) at various concentrations were studied. The phantoms were irradiated by various laser powers for 5 minutes. The temperature changes in each phantom was firstly calculated using COMSOL Multiphysics software. Also, each phantom was irradiated by laser and MR thermometry was performed to validate the simulation results. A reasonable correlation between simulation and MR thermometry was obtained (R=0.92). The error interval between calculations and experiments was ranged from ±3% to ±6%. It was clearly evident that laser irradiation conditions and nanoparticle characteristics affected the temperature rise profile. Spherical 20nm gold nanoparticles had better thermal efficiency and generated higher level of heat. The protocol suggested in this study may be appropriate to make a pre-clinical calculation and effect visualization for any nanoparticles-based PTT procedure before entrance into the clinics.
关键词： Nanotechnology,Cancer,Thermometry,Laser,Photothermal effects
更新于2025-09-12 10:27:22
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Anatomic and Thermometric Analysis of Cranial Nerve Palsy after Laser Amygdalohippocampotomy for Mesial Temporal Lobe Epilepsy
摘要： BACKGROUND: Laser interstitial thermal therapy (LITT) is a minimally invasive therapy for treating medication-resistant mesial temporal lobe epilepsy. Cranial nerve (CN) palsy has been reported as a procedural complication, but the mechanism of this complication is not understood. OBJECTIVE: To identify the cause of postoperative CN palsy after LITT. METHODS: Four medial temporal lobe epilepsy patients with CN palsy after LITT were identified for comparison with 22 consecutive patients with no palsy. We evaluated individual variation in the distance between CN III and the uncus, and CN IV and the parahippocampal gyrus using preoperative T1- and T2-weighted magnetic resonance (MR) images. Intraoperative MR thermometry was used to estimate temperature changes. RESULTS: CN III (n = 2) and CN IV palsies (n = 2) were reported. On preoperative imaging, the majority of identified CN III (54%) and CN IV (43%) were located within 1 to 2 mm of the uncus and parahippocampal gyrus tissue border, respectively. Affected CN III and CN IV were more likely to be found < 1 mm of the tissue border (PCNIII = .03, PCNIV < .01; chi-squared test). Retrospective assessment of thermal profile during ablation showed higher temperature rise along the mesial temporal lobe tissue border in affected CNs than unaffected CNs after controlling for distance (12.9?C vs 5.8?C; P = .03; 2-sample t-test). CONCLUSION: CN palsy after LITT likely results from direct heating of the respective CN running at extreme proximity to the mesial temporal lobe. Low-temperature thresholds set at the border of the mesial temporal lobe in patients whose CNs are at close proximity may reduce this risk.
关键词： LITT,MR thermometry,Mesial temporal lobe epilepsy,Laser amygdalohippocampotomy,Cranial nerve palsy
更新于2025-09-12 10:27:22
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Infrared- Thermometer-Based Detection of Optical Fiber Breakage in Structure
摘要： We show that infrared thermometry can be exploited to detect breakage points of optical fibers embedded in structures. This method has such advantages as real-time operation, cost efficiency, and visual display on site.
关键词： infrared thermometry,carbon fiber-reinforced plastics,structural health monitoring
更新于2025-09-11 14:15:04