Vector diffraction theory is applied to the case of focused TEM(00) Gaussian beams passing through a spatially limiting aperture in order to investigate the propagation of these clipped focused-Gaussian beams. Beam distributions at different axial distances show that a traditional M(2) propagation model cannot be used for the propagation of clipped focus-Gaussian beams. Using Luneberg's vector diffraction theory and Fresnel approximations, an analytical model for the on-axis transverse and longitudinal electric fields and intensity distributions is presented including predictions of the maximum obtainable intensity. In addition, an analytical expression is provided for the longitudinal component of the electric field of a TEM(00) mode unperturbed Gaussian beam. Experimental results are also presented and compared to the model's predictions.
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http://dx.doi.org/10.1364/OE.18.004023 | DOI Listing |
Phys Rev Lett
December 2024
Université Grenoble Alpes, Grenoble INP, CEA, IRIG, PHELIQS, 38000 Grenoble, France.
The antiferromagnetic structure of Yb_{3}Ga_{5}O_{12} is identified by neutron diffraction experiments below the previously known transition at T_{λ}=54 mK. The magnetic propagation vector is found to be k=(1/2,1/2,0), an unusual wave vector in the garnet structure. The associated complex magnetic structure highlights the role of exchange interactions in a nearly isotropic system dominated by dipolar interactions and finds echoes with exotic structures theoretically proposed.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany.
We present a high-resolution single crystal x-ray diffraction study of kagome superconductor CsV_{3}Sb_{5}, exploring its response to variations in pressure and temperature. We discover that at low temperatures, the structural modulations of the electronic superlattice, commonly associated with charge-density-wave order, undergo a transformation around p∼0.7 GPa from the familiar 2×2 pattern to a long-range-ordered modulation at wave vector q=(0,3/8,1/2).
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Discovery Pharmaceutical Sciences, Merck & Co., Inc., West Point, Pennsylvania 19486, United States.
Nonspecific protein-protein interactions (PPIs) are key to understanding the behavior of proteins in solutions. However, experimentally measuring anisotropic PPIs as a function of orientation and distance has been challenging. Here, we propose to measure a new parameter, the generalized second virial coefficient, (), to address this challenge.
View Article and Find Full Text PDFIn recent years, structured beams have emerged as an attractive and promising area of research, and nondiffracting beams and vector beams stand out as two particularly important categories of structured beams. Recognizing the significance of both beams, it is valuable to build a connection between these two kinds of structured beams. Here, we propose a kind of multi-periodic full Poincaré beam (MP-FPB), whose polarization states can cover the Poincaré sphere (PS) surface multiple times.
View Article and Find Full Text PDFNat Commun
December 2024
Max Planck Institute for the Science of Light, Erlangen, Germany.
Driven by human ingenuity and creativity, the discovery of super-resolution techniques, which circumvent the classical diffraction limit of light, represent a leap in optical microscopy. However, the vast space encompassing all possible experimental configurations suggests that some powerful concepts and techniques might have not been discovered yet, and might never be with a human-driven direct design approach. Thus, AI-based exploration techniques could provide enormous benefit, by exploring this space in a fast, unbiased way.
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