Digital inline pump-probe holography can be applied to estimate parameters of samples' optical nonlinear properties. Here we propose a mathematical model to describe noncollinear degenerate phase modulation in samples with inhomogeneities of nonlinear refractive index over all three dimensions, namely, two-layered samples and samples with local impurities. The impact of sample parameters in the considered configurations is analyzed. We show that analysis of inline digital holograms obtained by time-resolved inline digital holography can be successfully used for rapid detection and characterization of various types of nonlinear refractive index inhomogeneities.
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http://dx.doi.org/10.1364/AO.415102 | DOI Listing |
Proc Natl Acad Sci U S A
November 2024
Department of Physics, University of Wisconsin, Milwaukee, WI 53201.
The Stoner instability remains a cornerstone for understanding metallic ferromagnets. This instability captures the interplay of Coulomb repulsion, Pauli exclusion, and twofold fermionic spin degeneracy. In materials with spin-orbit coupling, this fermionic spin is generalized to a twofold degenerate pseudospin which is typically believed to have symmetry properties as spin.
View Article and Find Full Text PDFWe propose a simple scheme of degenerate spontaneous parametric down-conversion (SPDC) in nonlinear metasurfaces or photonic crystal slabs with quasi-guided modes. It employs a band crossing between even- and odd-parity quasi-guided mode bands inside the light cone (above the light line) and a selection rule in the conversion efficiency of the SPDC. The efficiency can be evaluated fully classically via the inverse process of noncollinear second-harmonic generation (SHG).
View Article and Find Full Text PDFPhys Chem Chem Phys
February 2024
Departamento de Química-Física, Universidad de Salamanca, Salamanca, 37008, Spain.
The O(P) + D → OD(Π) + D reaction presents the peculiarity of taking place on two different potential energy surfaces (PESs) of different symmetry, A' and A'', which become degenerate for collinear configurations where the saddle-point of the reaction is located. The degeneracy is broken for non-collinear approaches with the energy on the A' PES rising more abruptly with the bending angle, making the frequency of this mode higher on the A' state. Consequently, the A' PES should be less reactive than the A'' one.
View Article and Find Full Text PDFMaterials (Basel)
November 2022
Nikolayev Institute of Inorganic Chemistry SB RAS, 3 Lavrentiev Avenue, 630090 Novosibirsk, Russia.
The first neutral 2D heterometallic assemblies based on orbitally degenerate heptacyanidorhenate(IV) were prepared and structurally characterized. An analysis of the magnetic data for the polycrystalline samples of PhP[{Mn(acacen)}Re(CN)]·Solv () and PPN[{Mn(acacen)}Re(CN)]·Solv () have shown that both materials display slow magnetic relaxation at temperatures below 10 and 21 K for and , respectively. Despite the presence of the same molecular magnetic modules that make up the anionic layers, the studied 2D networks differ significantly in magnetic anisotropy, having a small coercive field (0.
View Article and Find Full Text PDFJ Imaging
March 2022
Faculty of Photonics, ITMO University, 197101 Saint-Petersburg, Russia.
We report on the application of time-resolved inline digital holography in the study of the nonlinear optical properties of quantum dots deposited onto sample glass. The Fresnel diffraction patterns of the probe pulse due to noncollinear degenerate phase modulation induced by a femtosecond pump pulse were extracted from the set of inline digital holograms and analyzed. The absolute values of the nonlinear refractive index of both the sample glass substrate and the deposited layer of quantum dots were evaluated using the proposed technique.
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