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high harmonic generation

E Narsimha Rao, G Vaitheeswaran, Ali H Reshak, S Auluck
We explore the effect of spin-orbit interaction (SOI) on the electronic and optical properties of CsPbCO3F using the full potential linear augmented plane wave method with the density functional theory (DFT) approach. CsPbCO3F is known for its high powder second harmonic generation (SHG) coefficient (13.4 times (d36 = 0.39 pm V(-1)) that of KH2PO4 (KDP)). Calculations are done for many exchange correlation (XC) potentials. After the inclusion of SOI, the calculated Tran-Blaha modified Becke-Johnson (TB-mBJ) band gap of 5...
November 17, 2017: Physical Chemistry Chemical Physics: PCCP
Guixin Li, Lin Wu, King Fai Li, Shumei Chen, Christian Schlickriede, Zhengji Xu, Siya Huang, Wen-Di Li, Yan Jun Liu, Edwin Yue-Bun Pun, Thomas Zentgraf, Kok Wai Cheah, Yu Luo, Shuang Zhang
The spin and orbital angular momentum (SAM and OAM) of light is providing a new gateway towards high capacity and robust optical communications. While the generation of light with angular momentum is well studied in linear optics, its further integration into nonlinear optical devices will open new avenues for increasing the capacity of optical communications through additional information channels at new frequencies. However, it has been challenging to manipulate the both SAM and OAM of nonlinear signals in harmonic generation processes with conventional nonlinear materials...
November 16, 2017: Nano Letters
Gabriele Materazzi, Carlo Enrico Ambrosini, Lorenzo Fregoli, Luigi De Napoli, Gianluca Frustaci, Valeria Matteucci, Piermarco Papini, Sohail Bakkar, Paolo Miccoli
Post-thyroidectomy neck hematoma represents a major concern for surgeons because it can result in severe and even life-threatening complications. In fact, postoperative hemorrhage may result in airway compression and respiratory distress, and therefore, effective hemostasis is an important goal in thyroid surgery. Postoperative hematoma occurs at a rate of approximately 0.1% to 1.1%. Almost all cases occur in the first 6 h after surgery and can be the result of several surgeon or patient factors. For many years the clamp-and-tie technique has been the most common way to divide the main vascular pedicles of the thyroid gland...
October 2017: Gland Surgery
Yang Li, Meng Kang, Junjun Shi, Ke Wu, Shunping Zhang, Hongxing Xu
Coherently adding up signal wave from different locations are a prerequisite for realizing efficient nonlinear optical processes in traditional optical configurations. While nonlinear optical processes in plasmonic waveguides with subwavelength light confinement are in principle desirable for enhancing nonlinear effects, so far it has been difficult to improve the efficiency due to the large momentum mismatch. Here we demonstrate, using remotely excited surface plasmon polaritons (SPPs), axial collimated but transversely divengent second harmonic (SH) generation in a single silver nanowire - monolayer molybdenum disulfide hybrid system...
November 15, 2017: Nano Letters
Matthieu Dubreuil, Sylvain Rivet, Yann Le Grand
A new high-speed second-harmonic generation (SHG) polarimetric method is reported. It is based on the spectral analysis of the SHG radiation emitted by a nonlinear medium excited with circularly polarized femtosecond laser pulses. The setup uses only passive components for polarization encoding and a fast spectrometer for spectral analysis. The method is validated on a z-cut quartz plate, then on a collagen-rich biological tissue with a view to single image polarization-resolved SHG microscopy.
November 15, 2017: Optics Letters
Nickolai Zhavoronkov, Mikhail Ivanov
Attosecond (1  as=10(-18)  s) pulses produced through high harmonic generation (HHG) are a basis for studies of electron dynamics during light-matter interaction on an electron's natural time scale. Extensively exploited HHG technology has, however, a few unsolved problems, where producing of circularly polarized or chiral attosecond pulses belongs to them. We have demonstrated experimentally a way to control the ellipticity of attosecond pulse trains produced via HHG in two-color, bi-circular laser fields...
November 15, 2017: Optics Letters
Fei-Fei Mao, Chun-Li Hu, Bing-Xuan Li, Jiang-Gao Mao
Partial substitution of iodate anions in La(IO3)3 by OH(-) or NO3(-) anion led to acentric La3(IO3)8(OH) and chiral La(IO3)2(NO3). The structure of La3(IO3)8(OH) can be seen as a complex three-dimensional (3D) network composed of two-dimensional [La3(IO3)2(OH)](6+) cationic layers that are further bridged by remaining iodate anions, or alternatively as a 3D network composed of one-dimensional [La3(IO3)6(OH)](2+) cationic columns being further interconnected by additional iodate anions, while the structure of La(IO3)2(NO3) can be seen as a novel 3D structure with planar NO3 groups serving as linkage between the [La3(IO3)6](3+) triple layers...
November 9, 2017: Inorganic Chemistry
A H Reshak
The electronic structure and linear and nonlinear optical susceptibility dispersions of lithium borate Li3B5O8(OH)2 are comprehensively investigated. The investigation is achieved on Li3B5O8(OH)2 in the form of single crystals, taking into account the influence of the packing of the structural units on the linear and nonlinear optical susceptibility dispersion. The calculations highlight that the BO3 structural unit packing is the main source of the large birefringence in Li3B5O8(OH)2 due to the high anisotropic electron distribution, and, hence, it affects the macroscopic second harmonic generation (SHG) coefficients...
November 9, 2017: Physical Chemistry Chemical Physics: PCCP
Konstantin O Nagornov, Anton N Kozhinov, Yury O Tsybin
Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) at the cyclotron frequency instead of the reduced cyclotron frequency has been experimentally demonstrated using narrow aperture detection electrode (NADEL) ICR cells. Here, based on the results of SIMION simulations, we provide the initial mechanistic insights into the cyclotron frequency regime generation in FT-ICR MS. The reason for cyclotron frequency regime is found to be a new type of a collective motion of ions with a certain dispersion in the initial characteristics, such as pre-excitation ion velocities, in a highly non-quadratic trapping potential as realized in NADEL ICR cells...
November 8, 2017: Journal of the American Society for Mass Spectrometry
Camilla Sekse, Arne Holst-Jensen, Ulrich Dobrindt, Gro S Johannessen, Weihua Li, Bjørn Spilsberg, Jianxin Shi
High-throughput sequencing (HTS) is becoming the state-of-the-art technology for typing of microbial isolates, especially in clinical samples. Yet, its application is still in its infancy for monitoring and outbreak investigations of foods. Here we review the published literature, covering not only bacterial but also viral and Eukaryote food pathogens, to assess the status and potential of HTS implementation to inform stakeholders, improve food safety and reduce outbreak impacts. The developments in sequencing technology and bioinformatics have outpaced the capacity to analyze and interpret the sequence data...
2017: Frontiers in Microbiology
Houguang Liu, Jinlei Cheng, Jianhua Yang, Zhushi Rao, Gang Cheng, Shanguo Yang, Xinsheng Huang, Mengli Wang
Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack...
November 2, 2017: Sensors
Huseyin Enes Salman, Yigit Yazicioglu
Arterial stenosis is a vascular pathology which leads to serious cardiovascular diseases. Blood flow through a constriction generates sound and vibration due to fluctuating turbulent pressures. Generated vibro-acoustic waves propagate through surrounding soft tissues and reach the skin surface and may provide valuable insight for noninvasive diagnostic purposes. Motivated by the aforementioned phenomena, vibration of constricted arteries is investigated employing computational models. The flow-induced pressure field in an artery is modeled as broadband harmonic pressure loading based on previous studies in the literature and applied on the inner artery wall...
October 2017: Journal of the Acoustical Society of America
Felicity McGrath, Allan S Johnson, Dane R Austin, Peter Hawkins, David Wood, Lukas Miseikis, Emma R Simpson, Marta Castillejo, Ricardo Torres, Susan Parker, Thomas Siegel, Jon P Marangos
We present an apparatus for performing gas phase high-harmonic generation spectroscopy of molecules primarily found in the liquid phase. Liquid molecular samples are heated in a temperature controlled bath and their vapour is used to back a continuous flow gas jet, with vapour pressures of over 1 bar possible. In order to demonstrate the system, we perform high harmonic spectroscopy experiments in benzene with a 1.8 μm driving field. Using the unique capabilities of the system, we obtain spectra that are nearly free from the effects of longitudinal phase-matching, amenable to comparison with advanced numerical modelling...
October 2017: Review of Scientific Instruments
J Wätzel, J Berakdar
Irradiating intercalated nanorings by optical vortices ignites a charge flow that emits coherent trains of high harmonic bursts with frequencies and time structures that are controllable by the topological charge of the driving vortex beam. Similar to synchrotron radiation, the polarization of emitted harmonics is also selectable by tuning to the appropriate emission angle with respect to the ring plane. The nonequilibrium orbital magnetic moment triggered in a ring tunnels quantum mechanically to smaller and larger rings leading respectively to high and low-frequency harmonic generation...
October 30, 2017: Optics Express
Bruno Majérus, Jérémy Butet, Gabriel D Bernasconi, Raziman Thottungal Valapu, Michaël Lobet, Luc Henrard, Oliver J F Martin
Optical second harmonic generation (SHG) from nanostructured graphene has been studied in the framework of classical electromagnetism using a surface integral equation method. Single disks and dimers are considered, demonstrating that the nonlinear conversion is enhanced when a localized surface plasmon resonance is excited at either the fundamental or second harmonic frequency. The proposed approach, beyond the electric dipole approximation used in the quantum description, reveals that SHG from graphene nanostructures with centrosymmetric shapes is possible when retardation effects and the excitation of high plasmonic modes at the second harmonic frequency are taken into account...
October 30, 2017: Optics Express
Zhi Fang, Zhan-Yu Hou, Feng Yang, Li-Juan Liu, Xiao-Yang Wang, Zu-Yan Xu, Chuang-Tian Chen
266 nm laser output in NaSr3Be3B3O9F4 crystal by the fourth harmonic generation process with a picosecond mode-locked Nd-based YAG laser has been done for the first time. When the input pumping energy was 870 μJ at 532 nm, a 280 μJ 266 nm UV laser was obtained and the corresponding conversion efficiency was 35.9%. Further investigations identified that NaSr3Be3B3O9F4 has a large acceptance angle width of 0.47 (mrad • cm), a small walk-off angle of 35.43 mrad and a large deff as 0.62 pm/V for the fourth harmonic generation...
October 30, 2017: Optics Express
S Patankar, S T Yang, J D Moody, G F Swadling, A C Erlandson, A J Bayramian, D Barker, P Datte, R L Acree, B Pepmeier, R E Madden, M R Borden, J S Ross
We report on two-photon absorption measurements at 213 nm of deep UV transmissible media, including LiF, MgF2, CaF2, BaF2, sapphire (Al2O3), and high-purity grades of fused-silica (SiO2). A high-stability 24 ps Nd:YAG laser operating at the 5th harmonic (213 nm) was used to generate a high-intensity, long-Rayleigh-length Gaussian focus inside the samples. The measurements of the fluoride crystals and sapphire indicate two-photon absorption coefficients between 0.004 and 0.82 cm/GW. We find that different grades of fused silica performed near identically for two-photon absorption; however, there are differences in linear losses associated with purity...
October 20, 2017: Applied Optics
Ethan J Ulrich, John J Sunderland, Brian J Smith, Imran Mohiuddin, Jessica Parkhurst, Kristin A Plichta, John M Buatti, Reinhard R Beichel
PURPOSE: Quality control plays an increasingly important role in quantitative PET imaging and is typically performed using phantoms. The purpose of this work was to develop and validate a fully-automated analysis method for two common PET/CT quality assurance phantoms: the NEMA NU-2 IQ and SNMMI/CTN oncology phantom. The algorithm was designed to only utilize the PET scan to enable the analysis of phantoms with thin-walled inserts. METHODS: We introduce a model-based method for automated analysis of phantoms with spherical inserts...
November 1, 2017: Medical Physics
Matthew M Harkenrider, Murat Surucu, Grant Harmon, Michael L Mysz, Steven M Shea, Joseph Yacoub, Ari Goldberg, Margaret Liotta, Abigail Winder, Ronald Potkul, John C Roeske, William Small
PURPOSE: The purpose of this study was to report early outcomes and assess the learning curve in a new MRI-based cervical brachytherapy program. METHODS: We accrued 33 patients prospectively, and only patients with ≥3 months' followup (n = 27) were assessed for disease control and toxicity. Eras were defined as first half and second half for the intracavitary (IC)-only era (n = 13 each), and the intracavitary/interstitial (IC/IS) era was separated by difference in applicator availability (n = 7)...
October 28, 2017: Brachytherapy
Aditi Bhattacherjee, Chaitanya Das Pemmaraju, Kirsten Schnorr, Andrew R Attar, Stephen R Leone
Molecular triplet states constitute a crucial gateway in the photochemical reactions of organic molecules by serving as a reservoir for the excess electronic energy. Here, we report the remarkable sensitivity of soft X-ray transient absorption spectroscopy for following the intricate electronic structure changes accompanying the non-adiabatic transition of an excited molecule from the singlet to the triplet manifold. Core-level X-ray spectroscopy at the carbon-1s K-edge (284 eV) is applied to identify the role of the triplet state (T1, (3)ππ*) in the ultraviolet-induced photochemistry of pentane-2,4-dione (acetylacetone, AcAc)...
November 9, 2017: Journal of the American Chemical Society
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