We demonstrate a variation of pump-probe spectroscopy that is particularly useful for laser frequency stabilization. The polarization-enhanced absorption spectroscopy (POLEAS) signal provides a significant improvement in signal-to-noise ratio over saturated absorption spectroscopy (SAS) for the important and commonly used atomic cycling transitions. The improvements can directly increase the short-term stability of a laser frequency lock, given sufficient servo loop bandwidth. The long-term stability of the POLEAS method, which is limited by environmental sensitivities, is comparable to that of SAS. The POLEAS signal is automatically Doppler-free, without requiring a separate Doppler subtraction beam, and lends itself to straightforward compact packaging. Finally, by increasing the amplitude of the desired (cycling) peak, while reducing the amplitude of all other peaks in the manifold, the POLEAS method eases the implementation of laser auto-locking schemes.
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http://dx.doi.org/10.1364/AO.52.008048 | DOI Listing |
Sci Rep
January 2025
Department of Botany and Microbiology, Faculty of Science, Alexandria University, Alexandria, Egypt.
Azurin, a bacterial blue-copper protein, has garnered significant attention as a potential anticancer drug in recent years. Among twenty Pseudomonas aeruginosa isolates, we identified one isolate that demonstrated potent and remarkable azurin synthesis using the VITEK 2 system and 16S rRNA sequencing. The presence of the azurin gene was confirmed in the genomic DNA using specific oligonucleotide primers, and azurin expression was also detected in the synthesized cDNA, which revealed that the azurin expression is active.
View Article and Find Full Text PDFAnal Chem
January 2025
School of Architecture and Civil Engineering, Northeast Petroleum University, Daqing 163318, China.
Multithermal fluid (MTF) component ratios and injection parameters are critical inputs in offshore heavy oil development, such as injection adjustment and monitoring, productivity prediction, and generator combustion process optimization. We implement simultaneous in situ diagnostics of two emblematic injection parameters, the gas-water ratio (GWR) and noncondensable gases proportion (NCGP), in a pilot-scale environment. A system-level integration of a novel laser absorption spectroscopy multigas sensor system based on integrating stray radiation suppression and a circular cell-enhanced strategy is proposed.
View Article and Find Full Text PDFTalanta
January 2025
Ampere - Laboratório de Plataformas Eletroquímicas. Departamento de Química, Universidade Federal de Santa Catarina, 880400-900, Florianópolis, SC, Brazil. Electronic address:
Nicotine (NIC) detection is vital for monitoring its presence in various environments, including tobacco products, electronic cigarettes, and clinical samples; NIC's widespread use and health implications necessitate precise and reliable detection methods as it is linked to diseases such as lung cancer and vascular disorders. In this study, we developed and characterized Au tadpole-like nanostructures immobilized onto titanium oxide (TiO) to provide a cost-effective and sensitive NIC detection material. The comprehensive characterization of the composite used transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), showing the robustness of the synthesis.
View Article and Find Full Text PDFBiosens Bioelectron
January 2025
NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614, Poznań, Poland. Electronic address:
Plasmonic surface lattice resonance (SLR) is a phenomenon in which individual localized surface plasmon resonances (LSPRs) excited in periodically-arranged plasmonic nanoparticles couple through the interaction with the propagating diffracted incident light. The SLR optical absorption peak is by at least one order of magnitude more intense than the LSPR one, making SLR superior for applications in which LSPR is commonly used. Recently, we have developed a route for the fabrication of spherical virus-like particles (VLPs) with plasmonic Au cores and protein coronas, where the LSPR in the cores amplifies vibrational Raman signals originating from protein-antibody interactions [ACS Synth.
View Article and Find Full Text PDFPLoS One
January 2025
Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Gangshan Hospital, Kaohsiung, Taiwan.
Background/purpose: Dyslipidemia, a hallmark of metabolic syndrome (MetS), contributes to atherosclerotic and cardiometabolic disorders. Due to days-long analysis, current clinical procedures for cardiotoxic blood lipid monitoring are unmet. This study used AI-assisted attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to identify MetS and precisely quantify multiple blood lipid levels with a blood sample of 0.
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