In this article, we propose a laptop photothermal reflectance measurement instrument assembled with optical fiber components. The primary feature of this instrument is that all of the optical routes for the pumping and probing beams, as well as the beam sources using a laser diode, are composed of optical fiber and optical fiber components. With this configuration, the problems related to the technical shortcomings of the conventional instrument can be solved completely. Our proposed instrument is also appropriate for in situ measurement of the thermoproperties of thin film. The dimensions of our instrument's case are 400 mm wide, 250 mm deep, and 60 mm tall, and its weight is approximately 1 kg, containing the power supply for driving the laser diode of the pumping beam and electronics for the detection of photothermal reflectance. These are at least 120 and 150 smaller than the volume and weight of the conventional commercial instrument, respectively. Nevertheless, it is only necessary to prepare a synchronous detection instrument for signal recovery (e.g., lock-in amplifier) with our instrument. To evaluate our instrument's thermoproperty measurement capability, we measured the thermal diffusivity and thermal conductivity of Au thin film. The thermal diffusivity of 1.5-microm-thick Au film measured by our instrument matched previously reported values within a margin of error of a few percent.
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http://dx.doi.org/10.1063/1.2736414 | DOI Listing |
Rev Sci Instrum
January 2025
Institute for Physical Chemistry, University of Göttingen, 37077 Göttingen, Germany.
Surface science instruments require excellent vacuum to ensure surface cleanliness; they also require control of sample temperature, both to clean the surface of contaminants and to control reaction rates at the surface, for example, for molecular beam epitaxy and studies of heterogeneous catalysis. Standard approaches to sample heating within high vacuum chambers involve passing current through filaments of refractory metals, which then heat the sample by convective, radiative, or electron bombardment induced heat transfer. Such hot filament methods lead to outgassing of molecules from neighboring materials that are inadvertently heated; they also produce electrons and ions that may interfere with other aspects of the surface science experiment.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
Department of Plasma Physics and Fusion Engineering, University of Science and Technology of China, Hefei 230026, China.
A novel all-fiber optic current sensor (FOCS) is designed specifically for the measurement of large transient currents based on the Faraday effect. A reciprocal symmetric structure is incorporated into the optical sensing loop, and the current dependent phase demodulation is achieved by using a passive optical fiber coupler and the homodyne detection scheme. This design offers several advantages, including structural simplicity, high voltage insulation, low noise, high linearity, and excellent frequency response, and is highly suitable for use in any system of high-voltage, high-power, and high-frequency in nature.
View Article and Find Full Text PDFAnal Chim Acta
March 2025
Zhejiang Key Laboratory of Advanced Optical Functional Materials and Devices, Ningbo University, Ningbo, 315211, China; Engineering Research Center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Province, Ningbo University, Ningbo, 315211, China. Electronic address:
Background: Permethrin is a pesticide used to kill insects, and once used in excess, it poses a great threat to the environment and human health, therefore, it is necessary to realize the rapid and accurate detection of permethrin. Fiber optic surface enhanced Raman scattering (SERS) probes have the advantages of small volume and can be used for remote monitoring, which have great potential for application in achieving in-situ detection of pesticide residues.
Results: Fiber taper waist (FTW) SERS probes modified by silver nanocubes-graphene oxide (Ag NCs-GO) composite structures were prepared for in situ detection of permethrin in lake water.
Am J Ophthalmol
January 2025
Hacettepe University School of Medicine, Department of Ophthalmology, Ankara, Turkey.
Objective: To evaluate the effects of Fanconi anemia (FA) on retinal and choroidal microvasculature using Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA).
Design: Cohort study with age-matched controls.
Subjects And Participants: This study included 11 eyes from 11 patients diagnosed with FA and 12 eyes from 12 age-matched healthy controls.
Neuron
January 2025
Department of Biochemistry, Weill Cornell Medicine, New York, NY 10065, USA; Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA. Electronic address:
Dissecting how membrane receptors regulate neural circuits is critical for deciphering principles of neuromodulation and mechanisms of drug action. Here, we use a battery of optical approaches to determine how presynaptic metabotropic glutamate receptor 2 (mGluR2) in the basolateral amygdala (BLA) controls anxiety-related behavior in mice. Using projection-specific photopharmacological activation, we find that mGluR2-mediated presynaptic inhibition of ventromedial prefrontal cortex (vmPFC)-BLA, but not posterior insular cortex (pIC)-BLA, connections produces a long-lasting decrease in spatial avoidance.
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