6,348 results match your criteria second-harmonic generation


2D van der Waals Layered [C(NH)]SOS Exhibits Desirable UV Nonlinear-Optical Trade-Off.

Inorg Chem 2021 Sep 22. Epub 2021 Sep 22.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.

It remains a challenge to develop UV nonlinear optical (NLO) crystals that can achieve a desirable trade-off on UV absorption edge, second harmonic generation (SHG), and birefringence. Here we report a thiosulfate UV NLO crystal of a 2D van der Waals layered structure, [C(NH)]SOS. Remarkably, this thiosulfate realizes the desired trade-off, with a short absorption edge of 254 nm, a strong SHG response of approximately 2. Read More

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September 2021

Microstructural Characterization of Resistance Artery Remodelling in Diabetes Mellitus.

J Vasc Res 2021 Sep 20:1-11. Epub 2021 Sep 20.

Department of Physics, University of Exeter, Exeter, United Kingdom.

Introduction: Microvascular remodelling is a symptom of cardiovascular disease. Despite the mechanical environment being recognized as a major contributor to the remodelling process, it is currently only understood in a rudimentary way.

Objective: A morphological and mechanical evaluation of the resistance vasculature in health and diabetes mellitus. Read More

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September 2021

What Mediates Fibrosis in the Tumor Microenvironment of Clear Renal Cell Carcinoma.

Front Genet 2021 3;12:725252. Epub 2021 Sep 3.

Department of Urology, Peking University People's Hospital, Beijing, China.

Previous studies have demonstrated that direct targeting of interstitial cancer-associated fibroblasts (CAF) and tumor fibrosis alone seemed to be an unpromising treatment option for malignant tumors. Therefore, it is necessary to further explore the mechanism of the influence of collagen and tumor fibrosis on the biological behavior of malignant tumors. The current study aimed to explore the effect of intratumor fibrosis on the prognosis of renal clear cell carcinoma (ccRCC) and its mechanism. Read More

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September 2021

Extremely large static and dynamic nonlinear optical response of small superalkali clusters NMM' (M, M'=Li, Na, K).

J Mol Graph Model 2021 Sep 10;109:108031. Epub 2021 Sep 10.

Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, KPK, 22060, Pakistan. Electronic address:

Exploring novel nonlinear optical (NLO) materials with excess electron properties is essential for advancing the use of excess electron compounds in optics. The studied superalkali clusters NMM' (M, M' = Li, Na, K) are thermodynamically stable and their binding energies range from -27.10 to -53. Read More

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September 2021

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe.

Nat Commun 2021 Sep 17;12(1):5500. Epub 2021 Sep 17.

Department of Physics, University of Regensburg, Regensburg, Germany.

Monolayer transition-metal dichalcogenides (TMDCs) show a wealth of exciton physics. Here, we report the existence of a new excitonic species, the high-lying exciton (HX), in single-layer WSe with an energy of ~3.4 eV, almost twice the band-edge A-exciton energy, with a linewidth as narrow as 5. Read More

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September 2021

Matter waves in atomic-molecular condensates with Feshbach resonance management.

Phys Rev E 2021 Aug;104(2-1):024222

Physical-Technical Institute, Uzbek Academy of Sciences, 100084 Tashkent, Uzbekistan.

The dynamics of matter waves in the atomic to molecular condensate transition with a time-modulated atomic scattering length is investigated. Both the cases of rapid and slow modulations are studied. In the case of rapid modulations, the average over oscillations for the system is derived. Read More

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Photocatalytic redox on the surface of colloidal silver nanoparticles revealed by second harmonic generation and two-photon luminescence.

Phys Chem Chem Phys 2021 Sep 15;23(35):19752-19759. Epub 2021 Sep 15.

Shenzhen Key Laboratory of Flexible Printed Electronics Technology, also School of Science, Harbin Institute of Technology (Shenzhen), University Town, Shenzhen 518055, Guangdong, China.

The redox of silver on the surface of Ag nanoparticles (AgNPs) has received extensive attention because of its significant impact on the biological, physical and chemical properties of AgNPs and their applications. Here we demonstrate that the surface redox reaction of AgNPs in colloids may be investigated by the second harmonic generation (SHG) and two-photon luminescence (TPL) emission from the AgNPs. It was revealed that the oxidation of silver on the surface of AgNPs was accelerated upon femtosecond laser excitation, accompanied by a decrease in the SHG and TPL emissions from the AgNPs. Read More

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September 2021

Ultrafast Charge-Transfer Dynamics in Twisted MoS/WSe Heterostructures.

ACS Nano 2021 Sep 14. Epub 2021 Sep 14.

Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032 Marburg, Germany.

Two-dimensional transition metal dichalcogenides offer a fascinating platform for creating van der Waals heterojunctions with exciting physical properties. Because of their typical type-II band alignment, photoexcited electrons and holes can separate interfacial charge transfer. Furthermore, the relative crystallographic alignment of the individual layers in these heterostructures represents an important degree of freedom. Read More

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September 2021

Comparison of the histology and stiffness of ventricles in Anura of different habitats.

J Biol Phys 2021 Sep 13;47(3):287-300. Epub 2021 Sep 13.

Department of Electrical and Mechanical Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi, 4668555, Japan.

Vertebrate hearts have undergone marked morphological and structural changes to adapt to different environments and lifestyles as part of the evolutionary process. Amphibians were the first vertebrates to migrate to land. Transition from aquatic to terrestrial environments required the ability to circulate blood against the force of gravity. Read More

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September 2021

Quantification of scar collagen texture and prediction of scar development via second harmonic generation images and a generative adversarial network.

Biomed Opt Express 2021 Aug 28;12(8):5305-5319. Epub 2021 Jul 28.

Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China.

Widely used for medical analysis, the texture of the human scar tissue is characterized by irregular and extensive types. The quantitative detection and analysis of the scar texture as enabled by image analysis technology is of great significance to clinical practice. However, the existing methods remain disadvantaged by various shortcomings, such as the inability to fully extract the features of texture. Read More

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Angstrom-Resolved Interfacial Structure in Buried Organic-Inorganic Junctions.

Phys Rev Lett 2021 Aug;127(9):096801

Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

Charge transport processes at interfaces play a crucial role in many processes. Here, the first soft x-ray second harmonic generation (SXR SHG) interfacial spectrum of a buried interface (boron-Parylene N) is reported. SXR SHG shows distinct spectral features that are not observed in x-ray absorption spectra, demonstrating its extraordinary interfacial sensitivity. Read More

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Fatigue Damage Evaluation of Short Carbon Fiber Reinforced Plastics Based on Thermoelastic Temperature Change and Second Harmonic Components of Thermal Signal.

Materials (Basel) 2021 Aug 30;14(17). Epub 2021 Aug 30.

DIC Corporation, Tokyo 103-8233, Japan.

Short fiber reinforced plastics (SFRPs) have excellent moldability and productivity compared to continuous fiber composites. In this study, thermoelastic stress analysis (TSA) was applied to detect delamination defects in short carbon fiber reinforced plastics (SCFRPs). The thermoelastic temperature change Δ, phase of thermal signal , and second harmonic temperature component Δ were measured. Read More

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Impact of radiofrequency ablation (RFA) on bone quality in a murine model of bone metastases.

PLoS One 2021 8;16(9):e0256076. Epub 2021 Sep 8.

Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.

Thermal therapies such as radiofrequency ablation (RFA) are gaining widespread clinical adoption in the local treatment of skeletal metastases. RFA has been shown to successfully destroy tumor cells, yet the impact of RFA on the quality of the surrounding bone has not been well characterized. RFA treatment was performed on femora of rats with bone metastases (osteolytic and osteoblastic) and healthy age matched rats. Read More

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September 2021

Influence of Temperature on Molecular Adsorption and Transport at Liposome Surfaces Studied by Molecular Dynamics Simulations and Second Harmonic Generation Spectroscopy.

J Phys Chem B 2021 Sep 8. Epub 2021 Sep 8.

Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, United States.

A fundamental understanding of the kinetics and thermodynamics of chemical interactions at the phospholipid bilayer interface is crucial for developing potential drug-delivery applications. Here we use molecular dynamics (MD) simulations and surface-sensitive second harmonic generation (SHG) spectroscopy to study the molecular adsorption and transport of a small organic cation, malachite green (MG), at the surface of 1,2-dioleoyl--glycero-3-phospho-(1'--glycerol) (DOPG) liposomes in water at different temperatures. The temperature-dependent adsorption isotherms, obtained by SHG measurements, provide information on adsorbate concentration, free energy of adsorption, and associated changes in enthalpy and entropy, showing that the adsorption process is exothermic, resulting in increased overall entropy. Read More

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September 2021

Investigation of Murine Vaginal Creep Response to Altered Mechanical Loads.

J Biomech Eng 2021 Sep 8. Epub 2021 Sep 8.

Tulane University, Department of Biomedical Engineering, 6823 St Charles Ave, New Orleans, LA 70118.

The vagina is a viscoelastic fibromuscular organ that provides support to the pelvic organs. The viscoelastic properties of the vagina are understudied but may be critical for pelvic stability. Most studies evaluate vaginal viscoelasticity under a single uniaxial load; however, the vagina is subjected to dynamic multiaxial loading in the body. Read More

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September 2021

Predictive constitutive modelling of arteries by deep learning.

J R Soc Interface 2021 Sep 8;18(182):20210411. Epub 2021 Sep 8.

Institute for Continuum and Material Mechanics, Hamburg University of Technology, Eißendorfer Straße 42, 21073 Hamburg, Germany.

The constitutive modelling of soft biological tissues has rapidly gained attention over the last 20 years. Current constitutive models can describe the mechanical properties of arterial tissue. Predicting these properties from microstructural information, however, remains an elusive goal. Read More

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September 2021

Unravelling the Effects of Cholesterol on the Second-Order Nonlinear Optical Responses of Di-8-ANEPPS Dye Embedded in Phosphatidylcholine Lipid Bilayers.

J Phys Chem B 2021 Sep 7;125(36):10195-10212. Epub 2021 Sep 7.

Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium.

Cholesterol is known for its role in maintaining the correct fluidity and rigidity of the animals cell membranes and thus their functions. Assessing the content and the role of cholesterol in lipid bilayers is therefore of crucial importance for a deeper understanding and control of membrane functioning. In this computational work, we investigate bilayers built from three types of glycerophospholipid phosphatidylcholine (PC) lipids, namely dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-oleoyl--glycero-3-phosphocholine (POPC), and dioleoylphosphatidylcholine (DOPC), and containing different amounts of cholesterol by analyzing the second-harmonic generation (SHG) nonlinear optical (NLO) response of a probe molecule, di-8-ANEPPS, inserted into the membranes. Read More

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September 2021

Giant All-Optical Modulation of Second-Harmonic Generation Mediated by Dark Excitons.

ACS Photonics 2021 Aug 13;8(8):2320-2328. Epub 2021 Jul 13.

Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.

All-optical control of nonlinear photonic processes in nanomaterials is of significant interest from a fundamental viewpoint and with regard to applications ranging from ultrafast data processing to spectroscopy and quantum technology. However, these applications rely on a high degree of control over the nonlinear response, which still remains elusive. Here, we demonstrate giant and broadband all-optical ultrafast modulation of second-harmonic generation (SHG) in monolayer transition-metal dichalcogenides mediated by the modified excitonic oscillation strength produced upon optical pumping. Read More

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Second harmonic generation theory for a helical macromolecule with high sensitivity to structural disorder.

Phys Chem Chem Phys 2021 Sep 22;23(36):20201-20217. Epub 2021 Sep 22.

Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, Ontario L5L1C6, Canada.

Microscopic theory for the second harmonic generation in a helical molecular system is developed in the minimal coupling representation including non-local interaction effects. At the second order to the field we find a compact expression which combines dipolar, quadrupolar and magnetic contributions. A detailed derivation of the response is performed to specifically isolate the quadratic coupling terms, which we denote as the coupling. Read More

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September 2021

A high-power and low-noise 532-nm continuous-wave laser for quantum gas microscopy.

Rev Sci Instrum 2021 Aug;92(8):083202

Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.

Low-noise, high-power 532-nm lasers are of great interest in many scientific research studies, such as gravitational wave detection and ultracold atom experiments. In particular, in the experiments of quantum gas microscopy, a large power of laser is necessary during the imaging process, while low noise is important for preventing the atoms from being heated up. In this work, we report on the generation of such a 532-nm continuous-wave laser by coherently combining two laser beams produced by single-pass second-harmonic generation. Read More

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Efficient generation of narrowband picosecond pulses from a femtosecond laser.

Rev Sci Instrum 2021 Aug;92(8):083001

State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.

In some applications of broadband ultrafast spectroscopy, such as surface sum frequency generation vibrational spectroscopy, femtosecond stimulated Raman spectroscopy (SRS), and coherent anti-Stokes Raman spectroscopy, a narrowband picosecond pulse is required to obtain a high spectral resolution. Here, we present a method to generate narrowband picosecond second harmonic (SH) and fundamental frequency (FF) pulses with high-conversion efficiency from a Ti:sapphire femtosecond laser amplifier. The narrowband picosecond SH pulse was generated based on the group velocity mismatch between the SH and FF pulses in a nonlinear crystal of β-barium borate (BBO). Read More

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Highly sensitive Fourier-transform coherent anti-Stokes Raman scattering spectroscopy via genetic algorithm pulse shaping.

Opt Lett 2021 Sep;46(17):4320-4323

We report highly sensitive Fourier-transform coherent anti-Stokes Raman scattering spectroscopy enabled by genetic algorithm (GA) pulse shaping for adaptive dispersion compensation. We show that the non-resonant four-wave mixing signal from water can be used as a fitness indicator for successful GA training. This method allows GA adaptation to sample measurement conditions and offers significantly improved performance compared to training using second-harmonic generation from a nonlinear crystal in place of the sample. Read More

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September 2021

The Rise of Infrared Nonlinear Optical Pnictides: Advances and Outlooks.

Chem Asian J 2021 Sep 1. Epub 2021 Sep 1.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fujian, 350002, P. R. China.

Infrared (IR) nonlinear optical (NLO) materials are the core devices to realize IR laser output, which are of vital importance in civilian and military fields. Non-centrosymmetric chalcogenide and pnictide compounds have already been widely accepted as favorable systems for IR-NLO materials. Compared to the extensively investigated IR-NLO chalcogenides during the past few decades, the research of non-centrosymmetric phosphides as IR-NLO materials is relatively scarce. Read More

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September 2021

SnPQ (Q = S, Se, S/Se): A Series of Lone-Pair Cationic Chalcogenophosphates Exhibiting Balanced NLO Activity Originating from SnQ Units.

Inorg Chem 2021 Sep 31;60(18):14390-14398. Epub 2021 Aug 31.

School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, People's Republic of China.

Two chalcogenophosphates, SnPSSe () and SnPSe (), are isostructural and crystallize in the monoclinic noncentrosymmetric space group . Their three-dimensional (3D) structures are constructed by [Sn(1)Q] hendecahedra and [Sn(2)Q] dodecahedra by sharing Q vertices and edges, leaving cavities for isolated [PQ] (Q = S/Se, Se) dimers. A second-harmonic-generation (SHG) measurement indicates that is phase-matchable with a response of approximately 1. Read More

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September 2021

Collagen V insufficiency in a mouse model for Ehlers Danlos-syndrome affects viscoelastic biomechanical properties explaining thin and brittle corneas.

Sci Rep 2021 Aug 30;11(1):17362. Epub 2021 Aug 30.

Laboratory of Ocular Cell Biology, CABMM, University of Zurich, Zurich, Switzerland.

Ehlers-Danlos syndrome (EDS) is a genetic disease leading to abnormalities in mechanical properties of different tissues. Here we quantify corneal biomechanical properties in an adult classic EDS mouse model using two different measurement approaches suited for murine corneal mechanical characterization and relate differences to stromal structure using Second Harmonic Generation (SHG) microscopy. Quasi-static Optical Coherence Elastography (OCE) was conducted non-invasively during ambient pressure modulation by - 3 mmHg. Read More

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Enhanced malachite green photolysis at the colloidal-aqueous interface.

Chemosphere 2021 Aug 25;287(Pt 1):131953. Epub 2021 Aug 25.

Department of Chemistry, Ball State University, Muncie, IN, 47306, USA. Electronic address:

Colloids, such as natural particulate matter and microplastics, can play a significant role in the fate and transport of organic contaminants. Specifically, these small nano-to micron-sized particles provide large surface area; thus, particle-aqueous interfacial chemistry becomes significant. In this work, we present an experimental investigation of interfacial photokinetics of malachite green cation (MG) adsorbed at the surface of polystyrene carboxyl (PSC) microspheres suspended in aqueous solution. Read More

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Li MTeO (M=Ti, Sn): Mid-Infrared Nonlinear Optical Crystal with Strong Second Harmonic Generation Response and Wide Transparency Range.

Angew Chem Int Ed Engl 2021 Aug 30. Epub 2021 Aug 30.

State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, China.

Oxide crystals have been widely used in nonlinear optics (NLO) in the ultraviolet-visible and near-infrared regions. Most traditional oxide crystals are restricted to the mid-infrared region due to their narrow transmission window. Hence, attempting to extend infrared cutoff wavelength of oxides has attracted much attention. Read More

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Quantitative structural imaging of keratoconic corneas using polarization-resolved SHG microscopy.

Biomed Opt Express 2021 Jul 16;12(7):4163-4178. Epub 2021 Jun 16.

Laboratory for Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France.

The human cornea is mainly composed of collagen fibrils aligned together within stacked lamellae. This lamellar structure can be affected in pathologies such as keratoconus, which is characterized by progressive corneal thinning and local steepening. In this study, we use polarization-resolved second harmonic generation (P-SHG) microscopy to characterize 8 control and 6 keratoconic human corneas. Read More

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Assessing collagen alterations in enzymatic degradation models of osteoarthritis via second harmonic generation microscopy.

Osteoarthritis Cartilage 2021 Aug 25. Epub 2021 Aug 25.

Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Dr, Madison, WI, 53706, USA. Electronic address:

Introduction: Structural changes in the collagen II architecture of osteoarthritis (OA) are poorly understood, which is a large shortcoming in the early diagnosis of this disease. Though degradation can be simulated by enzymes including trypsin and bacterial collagenase, the specific structural features of each digestion and their relationship to naturally occurring OA remain unclear.

Experimental Design: We used collagen sensitive/specific Second Harmonic Generation (SHG) microscopy in conjunction with optical scattering measurements to probe the resulting architecture changes in bovine knee cartilage upon trypsin and collagenase degradation. Read More

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