We experimentally and numerically study the effect of ultrafast temporal correlations in two-stage frequency upconversion pumping by using intense twin beams. Enhancement in the upconversion efficiency of each stage due to ultrafast temporal correlation is evaluated by varying the time delay between pumping beams. It is found that the temporal correlation of the twin beams is transferred to the first upconverted beam, thereby also enhancing the efficiency of the second sum-frequency generation (SFG). This result suggests that temporal correlations play an important role in enhancing the efficiency of light sources that incorporate a parametric downconversion process.
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http://dx.doi.org/10.1364/OL.522156 | DOI Listing |
Phys Rev Lett
December 2024
Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
The tomography of photonic quantum states is key in quantum optics, impacting quantum sensing, computing, and communication. Conventional detectors are limited in their temporal and spatial resolution, hampering high-rate quantum communication and local addressing of photonic circuits. Here, we propose to utilize free electron-photon interactions for quantum state tomography, introducing electron homodyne detection with potential for femtosecond-temporal and nanometer-spatial resolutions.
View Article and Find Full Text PDFSci Rep
December 2024
Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132, Kassel, Germany.
The ultrafast ionic dynamics in solids induced by intense femtosecond laser excitation are controlled by two fundamentally different yet interrelated phenomena. First, the substantial generation of hot electron-hole pairs by the laser pulse modifies the interatomic bonding strength and characteristics, inducing nonthermal ionic motion. Second, incoherent electron-ion collisions facilitate thermal equilibration between electrons and ions, achieving a uniform temperature on a picosecond timescale.
View Article and Find Full Text PDFEJNMMI Phys
December 2024
Department of Nuclear Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Center for Rare Diseases Research, Beijing Key Laboratory of Molecular Targeted Diagnosis and Therapy in Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, 1# Shuaifuyuan, Dongcheng District, Beijing, 100730, China.
Background: There is a need for faster amyloid PET scans to reduce patients' discomfort, minimize movement artifacts, and increase throughput. The recently introduced uMI Panorama PET/CT system featuring enhanced spatial resolution and sub-200ps TOF offers the potential for shorter scan duration without sacrificing image quality or efficacy to detect Aβ deposition. The study aims to establish a faster acquisition protocol for [F]florbetapir PET imaging using digital PET/CT scanner uMI Panorama, while ensuring adequate image quality and amyloid-β (Aβ) detectability comparable to the standard 10-minute scan.
View Article and Find Full Text PDFIn this Letter, we present a theoretical study based on the Lorentz function and harmonic oscillator model to explore temporal dynamics of charge transfer plasmon (CTP) resonances. By fitting scattering curves and near-field oscillations, we determine the dephasing time of CTP modes in conductively connected gold nanodisk dimers. We show that, compared with the well-known particle plasmon and dimer plasmon modes, the CTP mode has a narrow spectral width and longer lifetime.
View Article and Find Full Text PDFJ Chem Theory Comput
December 2024
Max Planck Institute for the Structure and Dynamics of Matter, Luruper Ch 149, Hamburg 22761, Germany.
High-harmonic generation (HHG) is a nonlinear process in which a material sample is irradiated by intense laser pulses, causing the emission of high harmonics of incident light. HHG has historically been explained by theories employing a classical electromagnetic field, successfully capturing its spectral and temporal characteristics. However, recent research indicates that quantum-optical effects naturally exist or can be artificially induced in HHG, such as entanglement between emitted harmonics.
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