We present a multipolar tensor analysis of second-harmonic radiation from arrays of noncentrosymmetric L-shaped gold nanoparticles. Our approach is based on the fundamental differences in the radiative properties of electric dipoles and higher multipoles, which give rise to differences in the nonlinear response tensors for the reflected and transmitted second-harmonic signals. The results are analyzed by dividing the tensors into symmetric (dipolar) and antisymmetric (higher multipolar) parts between the two directions. The nonlinear response is found to be dominated by a tensor component, not resolved earlier [Phys. Rev. Lett. 98, 167403 (2007)], which is associated with chiral symmetry breaking of the sample and which also contains a strong multipolar contribution. The results are explained by a phenomenological model where asymmetrically-distributed defects on opposite sides of the particles give rise to dipolar and quadrupolar second-harmonic emission.
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http://dx.doi.org/10.1364/oe.16.017196 | DOI Listing |
J Chem Phys
January 2025
Institut Lumière Matière, Université de Lyon, UMR 5306 CNRS, Université Claude Bernard Lyon 1, 69622 cedex Villeurbanne, France.
Liquid water still remains an ubiquitous liquid whose molecular organization requires careful investigation. In this work, we present a study of the second harmonic scattering (SHS) intensity for two different scattering angles, namely, the forward and the right angle geometries. This method performed at optical wavelengths is indeed selective toward long correlation lengths.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Functional Crystals Lab, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Tetrahedral halides with broad transparency and large second harmonic effects have the potential to serve as mid-infrared wide-bandgap materials with balanced nonlinear-optical (NLO) properties. However, their regular tetrahedral motifs tend to exhibit low optical birefringence (Δ < 0.03) due to limited structural anisotropy, which constrains their practical phase-matched capability.
View Article and Find Full Text PDFUltrasonics
January 2025
College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. Electronic address:
This study delves into the feasibility of leveraging quasi-static component (QSC) generation during primary Lamb wave propagation to discern subtle alterations in the interfacial properties of a two-layered plate. Unlike the second-harmonic generation of Lamb waves, QSC generation doesn't necessitate precise phase-velocity matching but rather requires an approximate matching of group velocities to ensure the emergence of cumulative growth effects. This unique characteristic empowers the QSC-based nonlinear ultrasonic method to effectively surmount the limitations associated with inherent dispersion and multimode traits of Lamb wave propagation.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry, University of California, Berkeley, CA 94720.
Combining Deep-UV second harmonic generation spectroscopy with molecular simulations, we confirm and quantify the specific adsorption of guanidinium cations to the air-water interface. Using a Langmuir analysis of measurements at multiple concentrations, we extract the Gibbs free energy of adsorption, finding it larger than typical thermal energies. Molecular simulations clarify the role of polarizability in tuning the thermodynamics of adsorption, and establish the preferential parallel alignment of guanidinium at the air-water interface.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Sogang University, Seoul 04107, Republic of Korea.
Two-dimensional (2D) organic-inorganic hybrid metal halides (OIMHs), characterized by noncentrosymmetric structures arising from the incorporation of chiral organic molecules that break inversion symmetry, have attracted significant attention. Particularly, chiral-polar 2D OIMHs offer a unique platform for multifunctional applications, as the coexistence of chirality and polarity enables the simultaneous manifestation of distinct properties such as nonlinear optical (NLO) effects, circular dichroism (CD), and ferroelectricity. In this study, we report the first synthesis of hafnium (Hf)-based chiral 2D OIMHs, achieved through the strategic incorporation of -substituents on the benzene ring of chiral organic components.
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