We propose an ultra-wideband photonic compressive receiver based on random codes shifting with image-frequency distinction. By shifting the center frequencies of two random codes in large frequency range, the receiving bandwidth is flexibly expanded. Simultaneously, the center frequencies of two random codes are slightly different. This difference is used to distinguish the "fixed" true RF signal from the differently located image-frequency signal. Based on this idea, our system solves the problem of limited receiving bandwidth of existing photonic compressive receivers. In the experiments, with two channels of only 780-MHz outputs, the sensing capability in the range of 11-41 GHz has been demonstrated. A multi-tone spectrum and a sparse radar-communication spectrum, composed of a linear frequency modulated (LFM) signal, a quadrature phase-shift keying (QPSK) signal and a single-tone signal, are both recovered.
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http://dx.doi.org/10.1364/OE.478282 | DOI Listing |
Nat Commun
January 2025
Center for High Pressure Science and Technology Advanced Research, Beijing, 100093, China.
Photon emission may be continuously produced from mechanical work through self-recoverable mechanoluminescence (ML). Significant progress has been made in high-performance ML materials in the past decades, but the rate-dependent ML kinetics remains poorly understood. Here, we have conducted systematic studies on the self-recoverable ML of Mn-doped SrZnOS (SrZnOS: Mn) under rapid compression up to ~10 GPa.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Centre Telč, 58856 Telč, Czech Republic.
The time-evolution of dynamics as well as microstructure and mechanical response of phosphate-based geopolymers was probed using x-ray photon correlation spectroscopy and rheological tests. The analyzed relaxation processes in the freshly prepared geopolymer mixes evidenced a q-independent mode of the autocorrelation function, ascribed to density fluctuations of the already established molecular network, undergoing reconfiguration without significant mass transport. Upon curing, the detected motions are localized and depict a system evolving toward structural arrest dominated by slower hyperdiffusive dynamics, characterized by a compressed exponential regime, pointing to a structural relaxation process subjected to internal stresses, in a context of marked dynamical and structural heterogeneity.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
Non-close-packed crystalline arrays of colloidal particles in an elastic matrix exhibit mechanochromism. However, small interparticle distances often limit the range of reversible color shifts and reduce reflectivity during a blueshift. A straightforward, reproducible strategy using matrix swelling to increase interparticle distance and improve mechanochromic performance is presented.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland.
We demonstrate high-resolution single-pixel imaging (SPI) in the visible and near-infrared wavelength ranges using an SPI framework that incorporates a novel, dedicated sampling scheme and a reconstruction algorithm optimized for the rapid imaging of highly sparse scenes at the native digital micromirror device (DMD) resolution of 1024 × 768. The reconstruction algorithm consists of two stages. In the first stage, the vector of SPI measurements is multiplied by the generalized inverse of the measurement matrix.
View Article and Find Full Text PDFEntropy (Basel)
November 2024
Institute of Theoretical Physics, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland.
We demonstrate that at the rim of the photon sphere of a black hole, the quantum statistics transition takes place in any multi-particle system of indistinguishable particles, which passes through this rim to the inside. The related local departure from Pauli exclusion principle restriction causes a decay of the internal structure of collective fermionic systems, including the collapse of Fermi spheres in compressed matter. The Fermi sphere decay is associated with the emission of electromagnetic radiation, taking away the energy and entropy of the falling matter without unitarity violation.
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