Read by QxMD icon Read

high harmonic generation

Salmaan H Inayat-Hussain, Masao Fukumura, A Muiz Aziz, Chai Meng Jin, Low Wei Jin, Rolando Garcia-Milian, Vasilis Vasiliou, Nicole C Deziel
BACKGROUND: Recent trends have witnessed the global growth of unconventional oil and gas (UOG) production. Epidemiologic studies have suggested associations between proximity to UOG operations with increased adverse birth outcomes and cancer, though specific potential etiologic agents have not yet been identified. To perform effective risk assessment of chemicals used in UOG production, the first step of hazard identification followed by prioritization specifically for reproductive toxicity, carcinogenicity and mutagenicity is crucial in an evidence-based risk assessment approach...
May 21, 2018: Environment International
Giancarlo Soavi, Gang Wang, Habib Rostami, David G Purdie, Domenico De Fazio, Teng Ma, Birong Luo, Junjia Wang, Anna K Ott, Duhee Yoon, Sean A Bourelle, Jakob E Muench, Ilya Goykhman, Stefano Dal Conte, Michele Celebrano, Andrea Tomadin, Marco Polini, Giulio Cerullo, Andrea C Ferrari
Optical harmonic generation occurs when high intensity light (>1010  W m- 2 ) interacts with a nonlinear material. Electrical control of the nonlinear optical response enables applications such as gate-tunable switches and frequency converters. Graphene displays exceptionally strong light-matter interaction and electrically and broadband tunable third-order nonlinear susceptibility. Here, we show that the third-harmonic generation efficiency in graphene can be increased by almost two orders of magnitude by controlling the Fermi energy and the incident photon energy...
May 21, 2018: Nature Nanotechnology
Xuehua Dong, Ling Huang, Qingyu Liu, Hongmei Zeng, Zhien Lin, Dingguo Xu, Guohong Zou
A promising UV nonlinear optical material, beryllium-free nitrate Ba2NO3(OH)3, has been synthesized via modified high-temperature solid state reactions in a self-made high-pressure apparatus which exhibits a perfect balance of a large second harmonic generation coefficient, an appropriate birefringence for phase matching, a short UV absorption cutoff edge and physicochemical stabilities.
May 21, 2018: Chemical Communications: Chem Comm
Dorien F O, Idhaliz Flores, Etienne Waelkens, Thomas D'Hooghe
A noninvasive biomarker-based test could help shorten the diagnostic delay for endometriosis. The most investigated biomarker sources are peripheral blood and endometrium. Discovery of endometriosis biomarkers is often hypothesis-driven, i.e. when one or a few biomarkers are investigated based on their role in the disease pathogenesis. Alternatively, a hypothesis-generating approach has been followed using the "omics" technologies. A variety of biomarkers for endometriosis have been investigated, but no biomarker has been validated for clinical use...
April 13, 2018: Best Practice & Research. Clinical Obstetrics & Gynaecology
Shuzeng Zhang, Xiongbing Li, Hyunjo Jeong, Hongwei Hu
Angle beam wedge transducers are widely used in nonlinear Rayleigh wave experiments as they can generate Rayleigh wave easily and produce high intensity nonlinear waves for detection. When such a transducer is used, the spurious harmonics (source nonlinearity) and wave diffraction may occur and will affect the measurement results, so it is essential to fully understand its acoustic nature. This paper experimentally investigates the nonlinear Rayleigh wave beam fields generated and received by angle beam wedge transducers, in which the theoretical predictions are based on the acoustic model developed previously for angle beam wedge transducers [S...
May 12, 2018: Ultrasonics
Liran Hareli, Lilya Lobachinsky, Georgiy Shoulga, Yaniv Eliezer, Linor Michaeli, Alon Bahabad
We demonstrate experimentally a relatively simple yet powerful all-optical enhancement and control technique for high harmonic generation. This is achieved by using as a pump beam two different spatial optical modes interfering together to realize tunable periodic quasi-phase matching of the interaction. With this technique, we demonstrate on-the-fly quasi-phase matching of harmonic orders 29-41 at ambient gas pressure levels of 50 and 100 Torr, where an up to 100-fold enhancement of the emission is observed...
May 4, 2018: Physical Review Letters
Xiaoli Huang, Qiyang Li, Xue Xiao, Shuping Jia, Yue Li, Zhigang Duan, Lei Bai, Ze Yuan, Lin Li, Zhihua Lin, Yonggang Zhao
We present here the synthesis of one enantiomeric pair of metal-organic framework materials comprised of a unique multioriented double-helix structure from an achiral spirocenter ligand. Our study clearly shows that the chiral MOF material encompasses concurrently multiple nonlinear-optical functions in the solid state: the noncentrosymmetric structural feature brings the chiral MOF high second-harmonic-generation efficiency; the incorporation of the spirocenter ligand can efficiently produce two-photon-excited photoluminescence with a larger-action cross-sectional value...
May 18, 2018: Inorganic Chemistry
Jiayue Tong, Matthew C Conte, Thomas Goldstein, K Sigfrid Yngvesson, Joseph C Bardin, Jun Yan
Graphene, a single atomic layer of covalently bonded carbon atoms, has been investigated intensively for optoelectronics and represents a promising candidate for high-speed electronics. Here we present a microwave mixer constructed as an asymmetrically-contacted two-terminal graphene device based on the thermoelectric effect. We report a 50 GHz (minimum) mixer bandwidth as well as 130 V/W extrinsic direct-detection responsivity. Anomalous second-harmonic generation due to self-mixing in our graphene detector is also observed...
May 16, 2018: Nano Letters
Farhad Akhoundi, Yukun Qin, N Peyghambarian, Jennifer K Barton, Khanh Kieu
We present the design, implementation and performance analysis of a compact multi-photon endoscope based on a piezo electric scanning tube. A miniature objective lens with a long working distance and a high numerical aperture (≈ 0.5) is designed to provide a diffraction limited spot size. Furthermore, a 1700 nm wavelength femtosecond fiber laser is used as an excitation source to overcome the scattering of biological tissues and reduce water absorption. Therefore, the novel optical system along with the unique wavelength allows us to increase the imaging depth...
May 1, 2018: Biomedical Optics Express
Zi-Yu Chen
We introduce two-color counterrotating circularly polarized laser fields as a way to spectrally control high harmonic generation (HHG) from relativistic plasma mirrors. Through particle-in-cell simulations, we show that only a selected group of harmonic orders can appear owing to the symmetry of the laser fields and the related conservation laws. By adjusting the intensity ratio of the two driving field components, we demonstrate the overall HHG efficiency, the relative intensity of allowed neighboring harmonic orders, and that the polarization state of the harmonic source can be tuned...
April 2018: Physical Review. E
Dieter Bauer, Kenneth K Hansen
High-harmonic generation in the two topological phases of a finite, one-dimensional, periodic structure is investigated using a self-consistent time-dependent density functional theory approach. For harmonic photon energies smaller than the band gap, the harmonic yield is found to differ by up to 14 orders of magnitude for the two topological phases. This giant topological effect is explained by the degree of destructive interference in the harmonic emission of all valence-band (and edge-state) electrons, which strongly depends on whether or not topological edge states are present...
April 27, 2018: Physical Review Letters
Allan S Johnson, Dane R Austin, David A Wood, Christian Brahms, Andrew Gregory, Konstantin B Holzner, Sebastian Jarosch, Esben W Larsen, Susan Parker, Christian S Strüber, Peng Ye, John W G Tisch, Jon P Marangos
Laser-driven high-harmonic generation provides the only demonstrated route to generating stable, tabletop attosecond x-ray pulses but has low flux compared to other x-ray technologies. We show that high-harmonic generation can produce higher photon energies and flux by using higher laser intensities than are typical, strongly ionizing the medium and creating plasma that reshapes the driving laser field. We obtain high harmonics capable of supporting attosecond pulses up to photon energies of 600 eV and a photon flux inside the water window (284 to 540 eV) 10 times higher than previous attosecond sources...
May 2018: Science Advances
Lei Wang, Sergey S Kruk, Kirill L Koshelev, Ivan I Kravchenko, Barry Luther-Davies, Yuri S Kivshar
Metasurfaces, two-dimensional lattices of nanoscale resonators, offer unique opportunities for functional flat optics and allow to control transmission, reflection, and polarization of a wavefront of light. Recently, all-dielectric metasurfaces reached remarkable efficiencies, often matching or outperforming conventional optical elements. Exploitation of nonlinear optical response of metasurfaces offers a paradigm shift in nonlinear optics, and dielectric nonlinear metasurfaces are expected to enrich subwavelength photonics by enhancing substantially nonlinear response of natural materials combined with efficient control of the phase of nonlinear waves...
May 11, 2018: Nano Letters
Yuan Hung Lo, Lingrong Zhao, Marcus Gallagher-Jones, Arjun Rana, Jared J Lodico, Weikun Xiao, B C Regan, Jianwei Miao
Coherent diffractive imaging (CDI) has been widely applied in the physical and biological sciences using synchrotron radiation, X-ray free-electron laser, high harmonic generation, electrons, and optical lasers. One of CDI's important applications is to probe dynamic phenomena with high spatiotemporal resolution. Here, we report the development of a general in situ CDI method for real-time imaging of dynamic processes in solution. By introducing a time-invariant overlapping region as real-space constraint, we simultaneously reconstructed a time series of complex exit wave of dynamic processes with robust and fast convergence...
May 8, 2018: Nature Communications
Kyle Frohna, Tejas Deshpande, John Harter, Wei Peng, Bradford A Barker, Jeffrey B Neaton, Steven G Louie, Osman M Bakr, David Hsieh, Marco Bernardi
Methylammonium lead iodide perovskite (MAPbI3 ) exhibits long charge carrier lifetimes that are linked to its high efficiency in solar cells. Yet, the mechanisms governing these unusual carrier dynamics are not completely understood. A leading hypothesis-disproved in this work-is that a large, static bulk Rashba effect slows down carrier recombination. Here, using second harmonic generation rotational anisotropy measurements on MAPbI3 crystals, we demonstrate that the bulk structure of tetragonal MAPbI3 is centrosymmetric with I4/mcm space group...
May 8, 2018: Nature Communications
Ettore Capoluongo, Giovanni Scambia, Jean-Marc Nabholtz
Background: Since the approval of the first poly (adenosine diphosphate [ADP]) ribose polymerase inhibitor (PARPi; olaparib [Lynparza™]) for platinum-sensitive relapsed high grade ovarian cancer, with either germline or somatic BRCA1/2 deleterious variants, the strategies for BRCA1/2 are dynamically changing. Along with germline testing within the context of familial or sporadic ovarian cancer, patients are now being referred for BRCA1/2 genetic assay above all for treatment decisions: in this setting tumour BRCA assay can allow to identify an estimated 3-9% of patients with peculiar somatic BRCA1/2 mutations...
April 13, 2018: Oncotarget
Tom Bolze, Patrick Nuernberger
Femtosecond vortex beams with adjustable temporal pulse shapes are generated. These shaped laser pulses are characterized in the spectral domain by determination of the spectral amplitude and phase as well as in the spatial domain by expansion of the beam profile in a superposition of Laguerre-Gaussian transversal laser modes. The experiments demonstrate that the temporal pulse shapes impressed with a pulse shaper based on a programmable liquid-crystal spatial light modulator are basically unaltered by subsequent transmission through a spiral phase plate, while a high-quality optical vortex is imposed...
May 1, 2018: Applied Optics
Jianwei Yu, Xiaoping Ouyang, Li Zhou, Youen Jiang, Baoqiang Zhu, Jianqiang Zhu
We study the feasibility of measuring pulse duration in the far field in high-energy petawatt lasers using single-shot autocorrelation. This single-shot autocorrelation technique makes use of parametric upconversion in media with randomly oriented ferroelectric domains, which supports transverse second-harmonic generation with two counter-propagating fundamental beams. We show that this technique possesses a large time window, capable of measuring pulses with temporal duration ranging from a sub-picosecond to tens of picoseconds...
May 1, 2018: Applied Optics
Paul Croaker, Akhilesh Mimani, Con Doolan, Nicole Kessissoglou
A simulation technique to analyse flow-induced noise problems that combines computational fluid dynamics (CFD), the boundary element method (BEM) and an aeroacoustic time-reversal (TR) source localisation method is presented. Hydrodynamic data are obtained from a high-fidelity CFD simulation of flow past a body and aeroacoustic sources are extracted based on Lighthill's acoustic analogy. The incident pressure field on the body due to the aeroacoustic sources is combined with a BEM representation of the body to obtain the spectrum of the direct, scattered and total acoustic pressure fields at far-field microphone locations...
April 2018: Journal of the Acoustical Society of America
Cédric Schmidt, Yoann Pertot, Tadas Balciunas, Kristina Zinchenko, Mary Matthews, Hans Jakob Wörner, Jean-Pierre Wolf
We present a 0.2 TW sub-two-cycle 1.8 µm carrier-envelope-phase stable source based on two-stage pulse compression by filamentation for driving high-order harmonic generation extending beyond the oxygen K absorption edge. The 1 kHz repetition rate, high temporal resolution enabled by the short 11.8 fs driving pulse duration, and bright high-order harmonics generated in helium make this an attractive source for solid-state and molecular-dynamics studies.
April 30, 2018: Optics Express
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"