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high harmonic generation

Lixin He, Qingbin Zhang, Pengfei Lan, Wei Cao, Xiaosong Zhu, Chunyang Zhai, Feng Wang, Wenjing Shi, Muzi Li, Xue-Bin Bian, Peixiang Lu, André D Bandrauk
Molecules constituted by different isotopes are different in vibrational modes, making it possible to elucidate the mechanism of a chemical reaction via the kinetic isotope effect. However, the real-time observation of the vibrational motion of isotopic nuclei in molecules is still challenging due to its ultrashort time scale. Here we demonstrate a method to monitor the nuclear vibration of isotopic molecules with the frequency modulation of high-order harmonic generation (HHG) during the laser-molecule interaction...
March 16, 2018: Nature Communications
Dimitar Popmintchev, Benjamin R Galloway, Ming-Chang Chen, Franklin Dollar, Christopher A Mancuso, Amelia Hankla, Luis Miaja-Avila, Galen O'Neil, Justin M Shaw, Guangyu Fan, Skirmantas Ališauskas, Giedrius Andriukaitis, Tadas Balčiunas, Oliver D Mücke, Audrius Pugzlys, Andrius Baltuška, Henry C Kapteyn, Tenio Popmintchev, Margaret M Murnane
Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6  keV. Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K- and L-absorption edges of solids at photon energies near 1 keV. We also report x-ray-absorption spectroscopy in the water window spectral region (284-543 eV) using a high flux high-order harmonic generation x-ray supercontinuum with 10^{9}  photons/s in 1% bandwidth, 3 orders of magnitude larger than has previously been possible using tabletop sources...
March 2, 2018: Physical Review Letters
Christopher J Lambert, Briana C Freshner, Arlen Chung, Tamara J Stevenson, D Miranda Bowles, Raheel Samuel, Bruce K Gale, Joshua L Bonkowsky
Zebrafish are a valuable model organism in biomedical research. Their rapid development, ability to model human diseases, utility for testing genetic variants identified from next-generation sequencing, amenity to CRISPR mutagenesis, and potential for therapeutic compound screening, has led to their wide-spread adoption in diverse fields of study. However, their power for large-scale screens is limited by the absence of automated genotyping tools for live animals. This constrains potential drug screen options, limits analysis of embryonic and larval phenotypes, and requires raising additional animals to adulthood to ensure obtaining an animal of the desired genotype...
2018: PloS One
Shi-Hao Zhang, Bang-Gui Liu
We propose through first-principles investigation that the GaTeCl monolayer is an excellent two-dimensional (2D) multiferroic with giant mechanical anisotropy. The calculated phonon spectrum, molecular dynamic simulations, and elastic moduli confirm its dynamic and mechanical stability, and our cleavage energy analysis shows that exfoliating one GaTeCl monolayer from the existing GaTeCl bulk is feasible. The calculated in-plane ferroelectric polarization reaches 578 pC m-1 . The energy barriers per formula unit of the ferroelastic 90° rotational and ferroelectric reversal transitions are 476 meV and 754 meV, respectively, being the greatest in the 2D multiferroics family so far...
March 15, 2018: Nanoscale
Kirby R Campbell, Bruce Wen, Emily M Shelton, Robert Swader, Benjamin L Cox, Kevin Eliceiri, Paul J Campagnola
Biological tissues have complex 3D collagen fiber architecture that cannot be fully visualized by conventional second harmonic generation (SHG) microscopy due to electric dipole considerations. We have developed a multi-view SHG imaging platform that successfully visualizes all orientations of collagen fibers. This is achieved by rotating tissues relative to the excitation laser plane of incidence, where the complete fibrillar structure is then visualized following registration and reconstruction. We evaluated high frequency and Gaussian weighted fusion reconstruction algorithms, and found the former approach performs better in terms of the resulting resolution...
October 2017: Optica
Carrie K Hui Mingalone, Zhiyi Liu, Judith M Hollander, Kirsten D Garvey, Averi L Gibson, Rose E Banks, Ming Zhang, Timothy E McAlindon, Heber C Nielsen, Irene Georgakoudi, Li Zeng
Osteoarthritis (OA) is a leading cause of chronic disability whose mechanism of pathogenesis is largely elusive. Local inflammation is thought to play a key role in OA progression, especially in injury-associated OA. While multiple inflammatory cytokines are detected, the timing and extent of overall inflammatory activities in early OA and the manner by which joint inflammation correlates with cartilage structural damage are still unclear. We induced OA via destabilization of the medial meniscus (DMM) in NFκB luciferase reporter mice, whose bioluminescent signal reflects the activity of NFκB, a central mediator of inflammation...
March 14, 2018: Laboratory Investigation; a Journal of Technical Methods and Pathology
Jue Hou, Joshua Williams, Elliot Botvinick, Eric Potma, Bruce J Tromberg
Label-free non-linear optical microscopy (NLOM) based on two-photon excited fluorescence (TPEF) from cofactors Nicotinamide Adenine Dinucleotide (NADH) and Flavin Adenine Dinucleotide (FAD+) is widely used for high-resolution cellular redox imaging. In this work, we combined three, label-free NLOM imaging methods to quantitatively characterize breast cancer cells and their relative invasive potential: 1) TPEF optical redox ratio (ORR = FAD+/NADH + FAD+), 2) coherent Raman scattering (CRS) of cellular lipids, and 3) second harmonic generation (SHG) of extracellular matrix (ECM) collagen...
March 13, 2018: Cancer Research
M Ruberti, P Decleva, V Averbukh
Here we present a fully ab initio study of the high-order harmonic generation (HHG) spectrum of aligned CO2 molecules. The calculations have been performed by using the molecular time-dependent (TD) B-spline algebraic diagrammatic construction (ADC) method. We quantitatively study how the sub-cycle laser-driven multi-channel dynamics, as reflected in the position of the dynamical minimum in the HHG spectrum, is affected by the full inclusion of both correlation-driven and laser-driven dipole interchannel couplings...
March 13, 2018: Physical Chemistry Chemical Physics: PCCP
Gregory Moille, Sylvain Combrié, Laurence Morgenroth, Gaëlle Lehoucq, Sébastien Sauvage, Moustafa El Kurdi, Philippe Boucaud, Alfredo de Rossi, Xavier Checoury
We demonstrate that conformal encapsulation using atomic layer deposition of GaAs nano-cavity resonator made of photonic crystal cavity prevents photo-induced oxidation. This improvement allows injecting a large quantity of energy in the resonator without any degradation of the material, thus enabling spectral stability of the resonance. We prove second harmonic and third harmonic generation over more than one decade of pump power variation, thanks to this encapsulation, with a total efficiency (ηSHG = 8.3 × 10-5 W-1 and ηTHG = 1...
March 5, 2018: Optics Express
A Comby, S Beaulieu, E Constant, D Descamps, S Petit, Y Mairesse
We propose and implement a method to determine the absolute density profile of a gas jet producing high-order harmonics. By measuring the transverse profile of the fluorescence emitted by the plasma, we retrieve the local density in the gas jet. We use this technique during the optimization of the high-harmonics of 515 nm, 10 µJ, 130 fs pulses at 500 kHz and find that we can generate in absorption-limited conditions.
March 5, 2018: Optics Express
Luxi Peng, Jinxiu Wen, Huanjun Chen, Zebo Zheng, Ningsheng Xu, Jun Chen, Shaozhi Deng, Fei Liu
Boron is a narrow-bandgap (1.56 eV) semiconductor with high melting-point, low-density, large Young's modulus and very high refractive index (3.03) close to silicon. Therefore, boron nanostructures is expected to possess strong visible-light scattering properties. However, photonic and optoelectronic properties of the boron nanostructures are seldom studied until now. In this paper, we have successfully prepared single-crystalline boron nanowire (BNW) arrays with high-density on Si substrate. All the BNWs are found to possess strong light-scattering behaviors in the visible regime...
March 12, 2018: Small
Min Luo, Fei Liang, Yunxia Song, Dan Zhao, Feng Xu, Ning Ye, Zheshuai Lin
Two novel noncentrosymmetric alkaline-earth fluorooxoborates, M2B10O14F6 (M=Ca, Sr), were synthesized and characterized. Both of these two isostructural compounds had layered [B5O7F3]∞ structures with large second harmonic generation (SHG) responses ranging from 2.3 to 2.5×KH2PO4 (KDP) and short UV absorption edges (<200 nm). And the first-principles calculation demonstrated that their NLO properties were supe-rior to those of KBBF. In contrast to the alkali fluorooxoborates, these two fluorooxoborates showed not only remarkable stabil-ity against air and moisture but also high thermal stability...
March 8, 2018: Journal of the American Chemical Society
Hongwei Yu, Nathan Koocher, James Rondinelli, P Shiv Halasyamani
Borate halides are an ideal materials class from which to design high-performance nonlinear optical (NLO) materials. Currently, borate fluorides, chlorides, and bromides are extensively investigated while borate iodide materials discovery remains rare due to perceived synthetic challenges. We report a new borate iodide, Pb2BO3I synthesized by a straightforward hydrothermal method. The Pb2BO3I chemical formula conceals that the compound exhibits a structure similiar to the well-known KBe2BO3F2 (KBBF), which we show supports the highest second-harmonic generation (SHG) at 1064 nm in the KBBF family, 10 x KH2PO4 (KDP), arising from the inclusion of Pb2+ and I- and the aforementioned crystal-chemistry...
March 7, 2018: Angewandte Chemie
Amel Slimani, Delphine Tardivo, Ivan V Panayotov, Bernard Levallois, Csilla Gergely, Frederic Cuisinier, Hervé Tassery, Thierry Cloitre, Elodie Terrer
Dentin carious lesion is a dynamic process that involves demineralization and collagen denaturation. Collagen type I is the major protein in dentin and it has been investigated based on its optical properties. Multiphoton microscopy (MPM) is a nonlinear imaging technique that reveals the caries process using the collagen two-photon excitation fluorescence (2PEF) and its second-harmonic generation (SHG). Combining the histological and the International Caries Detection and Assessment System (ICDAS) classifications with nonlinear optical spectroscopy (NLOS), 2PEF and SHG intensities of enamel and dentin were highly altered during the caries process...
March 6, 2018: Caries Research
Miriding Mutailipu, Min Zhang, Bingbing Zhang, Liying Wang, Zhihua Yang, Xin Zhou, Shilie Pan
Fluorooxoborates, benefiting from the large optical band gap, high anisotropy, and ever-greater possibility to form noncentrosymmetric structures activated by the large polarization of the [BOxF4-x](x+1)- building blocks, have been considered as the new fertile fields for searching the ultraviolet (UV) and deep-UV nonlinear optical (NLO) materials. Here, we report the first asymmetric alkaline-earth metal fluorooxoborate SrB5O7F3, which is rationally designed by taking the classic Sr2Be2B2O7 (SBBO) as a maternal structure...
March 2, 2018: Angewandte Chemie
Abdullah Alharbi, Andrey E Boguslavskiy, Dane Austin, Nicholas Thiré, D Wood, P Hawkins, Felicity McGrath, A S Johnson, I Lopez-Quintas, Bruno Schmidt, Francois Légaré, J P Marangos, Anh-Thu Le, Ravi Bhardwaj
Structural isomers, molecules having the same chemical formula but with atoms bonded in different order, are hard to identify using conventional spectroscopy and mass spectrometry. They exhibit virtually indistinguishable mass spectra when ionized by electrons. Laser mass spectrometry based on photoionization of the isomers has emerged as a promising alternative but requires shaped ultrafast laser pulses. Here we use transform limited femtosecond pulses to distinguish the isomers using two methods. First, we probe doubly charged parent ions with circularly polarized light...
February 28, 2018: Scientific Reports
Ichiro Inoue, Taito Osaka, Kenji Tamasaku, Haruhiko Ohashi, Hiroshi Yamazaki, Shunji Goto, Makina Yabashi
An X-ray prism for the extraction of a specific harmonic of undulator radiation is proposed. By using the prism in a grazing incidence geometry, the beam axes of fundamental and harmonics of undulator radiation are separated with large angles over 10 µrad, which enables the selection of a specific harmonic with the help of apertures, while keeping a high photon flux. The concept of the harmonic separation was experimentally confirmed using X-ray beams from the X-ray free-electron laser SACLA.
March 1, 2018: Journal of Synchrotron Radiation
Eduard Prat, Sven Reiche
X-ray free-electron lasers (FELs) are cutting-edge scientific tools able to generate transversely coherent radiation with very high power and ultra-short pulse durations. The self-seeding mechanism has been proven to increase the longitudinal coherence of the FEL radiation but its efficiency could be significantly improved, especially for soft X-rays. This paper proposes the enhancement of the performance of self-seeding by combining it with the harmonic generation mechanism. In particular, by starting the process with a subharmonic of the wavelength of interest, the coherence of the produced radiation is improved, the undulator beamline becomes more compact, and the monochromator realization is simplified...
March 1, 2018: Journal of Synchrotron Radiation
Nicolas Tancogne-Dejean, Angel Rubio
The generation of high-order harmonics from atomic and molecular gases enables the production of high-energy photons and ultrashort isolated pulses. Obtaining efficiently similar photon energy from solid-state systems could lead, for instance, to more compact extreme ultraviolet and soft x-ray sources. We demonstrate from ab initio simulations that it is possible to generate high-order harmonics from free-standing monolayer materials, with an energy cutoff similar to that of atomic and molecular gases. In the limit in which electrons are driven by the pump laser perpendicularly to the monolayer, they behave qualitatively the same as the electrons responsible for high-harmonic generation (HHG) in atoms, where their trajectories are described by the widely used semiclassical model, and exhibit real-space trajectories similar to those of the atomic case...
February 2018: Science Advances
Álvaro Jiménez-Galán, Gopal Dixit, Serguei Patchkovskii, Olga Smirnova, Felipe Morales, Misha Ivanov
High harmonic generation in multi-color laser fields opens the opportunity of generating isolated attosecond pulses with high ellipticity. Such pulses hold the potential for time-resolving chiral electronic, magnetization, and spin dynamics at their natural timescale. However, this potential cannot be realized without characterizing the exact polarization state of light on the attosecond timescale. Here we propose and numerically demonstrate a complete solution of this problem. Our solution exploits the extrinsic two-dimensional chirality induced in an atom interacting with the chiral attosecond pulse and a linearly polarized infrared probe...
February 27, 2018: Nature Communications
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