We are utilizing recent advances in ultrafast laser technology and recent discoveries in optimal shaping of laser pulses to significantly enhance the stand-off detection of explosives via control of molecular processes at the quantum level. Optimal dynamic detection of explosives is a method whereby the selectivity and sensitivity of any of a number of nonlinear spectroscopic methods are enhanced using optimal shaping of ultrafast laser pulses. We have recently investigated the Gerchberg-Saxton algorithm as a method to very quickly estimate the optimal spectral phase for a given analyte from its spontaneous Raman spectrum and the ultrafast laser pulse spectrum. Results for obtaining selective coherent anti-Stokes Raman spectra (CARS) for an analyte in a mixture, while suppressing the CARS signals from the other mixture components, are compared for the Gerchberg-Saxton method versus previously obtained results from closed-loop machine-learning optimization using evolutionary strategies.
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http://dx.doi.org/10.1007/s00216-011-5348-x | DOI Listing |
Phys Rev Lett
December 2024
European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble, CS 40220, 38043, France.
Studying the properties and phase diagram of iron at high-pressure and high-temperature conditions has relevant implications for Earth's inner structure and dynamics and the temperature of the inner core boundary (ICB) at 330 GPa. Also, a hexagonal-closed packed to body-centered cubic (bcc) phase transition has been predicted by many theoretical works but observed only in a few experiments. The recent coupling of high-power laser with advanced x-ray sources from synchrotrons allows for novel approaches to address these issues.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China.
With the advancement of high harmonic generation and X-ray free-electron lasers (XFELs) to the attosecond domain, the studies of the ultrafast electron and spin dynamics became possible. Yet, the methods for efficient control and measurement of the quantum state are to be further developed. In this publication, we propose using magnetic X-ray scattering (MXS) for resolving the molecular spin-state dynamics and establish a complete protocol to simulate MXS diffraction patterns in molecules with ab initio quantum chemistry based on the multiconfigurational method.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
College of Optical, Mechanical and Electrical Engineering, Zhejiang A&F University, Lin'an 311300, China.
As a member of the chalcogenide family, NiSe exhibits a direct bandgap of 1.74 eV, making it a promising candidate for nonlinear optical devices. However, its potential in the near-infrared region of the telecommunication band has not been fully explored.
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 PDFBiosensors (Basel)
December 2024
Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen 518107, China.
The demand for non-invasive, real-time health monitoring has driven advancements in wearable sensors for tracking biomarkers in sweat. Ammonium ions (NH) in sweat serve as indicators of metabolic function, muscle fatigue, and kidney health. Although current ion-selective all-solid-state printed sensors based on nanocomposites typically exhibit good sensitivity (~50 mV/log [NH]), low detection limits (LOD ranging from 10 to 10 M), and wide linearity ranges (from 10 to 10 M), few have reported the stability test results necessary for their integration into commercial products for future practical applications.
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