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high harmonic generation

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https://www.readbyqxmd.com/read/28225007/full-3d-modelling-of-pulse-propagation-enables-efficient-nonlinear-frequency-conversion-with-low-energy-laser-pulses-in-a-single-element-tripler
#1
Tomasz M Kardaś, Michał Nejbauer, Paweł Wnuk, Bojan Resan, Czesław Radzewicz, Piotr Wasylczyk
Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus...
February 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28224998/plasmon-assisted-high-harmonic-generation-in-graphene
#2
Joel D Cox, Andrea Marini, F Javier García de Abajo
High-harmonic generation in condensed-matter systems is both a source of fundamental insight into quantum electron motion and a promising candidate to realize compact ultraviolet and ultrafast light sources. While graphene is anticipated to efficiently generate high-order harmonics due to its anharmonic charge-carrier dispersion, experiments performed on extended samples using THz illumination have revealed only a weak effect. The situation is further complicated by the enormous electromagnetic field intensities required by this highly nonperturbative nonlinear optical phenomenon...
February 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28210879/theoretical-study-of-the-spectroscopic-and-nonlinear-optical-properties-of-trans-and-cis-4-hydroxyazobenzene
#3
Hai-Peng Li, Ze-Tong Bi, Wen-Yue Fu, Run-Feng Xu, Yi Zhang, Xiao-Peng Shen, Ming-Xue Li, Gang Tang, Kui Han
We investigate the molecular structure, vibrational and electronic absorption spectra, and electronic hyperpolarizabilities of trans and cis isomers of 4-hydroxyazobenzene (HOAB) via density functional theory. Results show that the azo dye exhibits a high third-order nonlinear optical response and good optical transparency. Both the basis set and the functional are important influences on the results obtained when calculating the absorption spectrum and NLO response. We also study the effect of the solvent on the electronic absorption spectrum to assess the ability of the functional to reproduce the experimental spectrum in combination with a suitable solvent model...
March 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28206879/development-and-validation-of-a-green-analytical-method-for-the-determination-of-norfloxacin-in-raw-material-by-ftir-spectrophotometry
#4
Jéssica Sayuri Hisano Natori, Eliane Gandolpho Tótoli, Hérida Regina Nunes Salgado
Norfloxacin is a broad-spectrum antimicrobial agent, widely used in humans and animals for the treatment of urinary tract infections. It is a second-generation fluoroquinolone. Several analytical methods to analyze norfloxacin have been described in the literature. However, most of them are complex and require the use of large amounts of organic solvents. This paper describes the development and validation of a green analytical method for the determination of norfloxacin in raw material by FTIR spectrophotometry...
November 1, 2016: Journal of AOAC International
https://www.readbyqxmd.com/read/28205510/controlling-second-harmonic-generation-at-the-nanoscale-with-monolithic-algaas-on-alox-antennas
#5
L Carletti, D Rocco, A Locatelli, C De Angelis, V F Gili, M Ravaro, I Favero, G Leo, M Finazzi, L Ghirardini, M Celebrano, G Marino, A V Zayats
We review recent achievements in the field of nanoscale nonlinear AlGaAs photonics based on all-dielectric optical antennas. After discussing the motivation and main technological challenges for the development of an AlGaAs monolithic platform for χ ((2)) nonlinear nanophotonics, we present numerical and experimental investigations of the second-order nonlinear response and physical reasons for high efficiency of second-order nonlinear interactions in the AlGaAs nano-antennas. In particular, we emphasize the role of the dipolar resonances at the fundamental frequency and the multipolar resonances at the second harmonic wavelength...
February 16, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28205306/multi-site-quality-and-variability-analysis-of-3d-fdg-pet-segmentations-based-on-phantom-and-clinical-image-data
#6
Reinhard R Beichel, Brian J Smith, Christian Bauer, Ethan J Ulrich, Payam Ahmadvand, Mikalai M Budzevich, Robert J Gillies, Dmitry Goldgof, Milan Grkovski, Ghassan Hamarneh, Qiao Huang, Paul E Kinahan, Charles M Laymon, James M Mountz, John P Muzi, Mark Muzi, Sadek Nehmeh, Matthew J Oborski, Yongqiang Tan, Binsheng Zhao, John J Sunderland, John M Buatti
PURPOSE: Radiomics utilizes a large number of image-derived features for quantifying tumor characteristics that can in turn be correlated with response and prognosis. Unfortunately, extraction and analysis of such image-based features is subject to measurement variability and bias. The challenge for radiomics is particularly acute in Positron Emission Tomography (PET) where limited resolution, a high noise component related to the limited stochastic nature of the raw data, and the wide variety of reconstruction options confound quantitative feature metrics...
February 2017: Medical Physics
https://www.readbyqxmd.com/read/28198871/generating-high-contrast-near-single-cycle-waveforms-with-third-order-dispersion-compensation
#7
Henry Timmers, Yuki Kobayashi, Kristina F Chang, Maurizio Reduzzi, Daniel M Neumark, Stephen R Leone
Femtosecond laser pulses lasting only a few optical periods hold the potential for probing and manipulating the electronic degrees of freedom within matter. However, the generation of high-contrast, few-cycle pulses in the high power limit still remains nontrivial. In this Letter, we present the application of ammonium dihydrogen phosphate (ADP) as an optical medium for compensating for the higher-order dispersion of a carrier-envelope stable few-cycle waveform centered at 735 nm. The ADP crystal is capable of removing the residual third-order dispersion present in the spectral phase of an input pulse, resulting in near-transform-limited 2...
February 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28196344/identification-characterization-and-in-silico-admet-prediction-of-roflumilast-degradation-products
#8
Mariana S Pinheiro, Gil M Viana, Bárbara de A Abrahim Vieira, Alessandra Mendonça Teles de Souza, Carlos Rangel Rodrigues, Rita de Cássia E E Marins, Lúcio M Cabral, Valéria P de Sousa
The present study reports the degradation behavior of roflumilast (RFL), a new drug developed for the treatment of chronic obstructive pulmonary disease. The degradation of RFL was tested under various stress conditions as per the guidelines of the International Conference on Harmonization. The degradation products (DPs) of RFL were identified, characterized and in silico predictions were made of their pharmacokinetic properties, absorption, distribution, metabolism, excretion and toxicity (ADMET). RFL was subjected to various stress conditions including photodegradation, alkaline and acidic hydrolysis, oxidative and metallic degradation...
February 6, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28186820/phase-matching-using-the-linear-electro-optic-effect
#9
Zijian Cui, Dean Liu, Jie Miao, Aihua Yang, Jianqiang Zhu
Phase matching is a necessary condition for achieving high-efficiency optical-frequency conversion. To date, practical means of accomplishing phase matching in homogeneous crystals remain limited, despite considerable efforts. Herein, we report a new class of methods aimed at achieving quasiperfect phase matching, based on controllable birefringence produced via the linear electro-optic effect, termed "voltage-tuning phase matching." The wave vectors of the induced polarization and the generated fields can be matched and maintained along the direction of propagation by introducing an external electric field...
January 27, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28182426/probing-the-near-field-of-second-harmonic-light-around-plasmonic-nanoantennas
#10
Bernd Metzger, Mario Hentschel, Harald Giessen
We introduce a new concept that enables sub-wavelength polarization-resolved probing of the second-harmonic near-field distribution of plasmonic nanostructures. As a local sensor this method utilizes aluminum nanoantennas, which are resonant to the second-harmonic wavelength and which allow to efficiently scatter the local second-harmonic light to the far-field. We place these sensors into the second-harmonic near-field generated by plasmonic nanostructures, and carefully vary their position and orientation...
February 9, 2017: Nano Letters
https://www.readbyqxmd.com/read/28180998/the-prognostic-value-and-pathobiological-significance-of-glasgow-microenvironment-score-in-gastric-cancer
#11
Zhi-Hua Zhou, Cheng-Dong Ji, Jiang Zhu, Hua-Liang Xiao, Hai-Bin Zhao, You-Hong Cui, Xiu-Wu Bian
PURPOSE: To evaluate the prognostic value and pathobiological significance of Glasgow microenvironment score (GMS), a parameter based on tumor stroma percentage and inflammatory cell infiltration, in gastric cancer. METHODS: A total of 225 cases of gastric cancer were histologically reviewed, and GMS was evaluated for each case. The association between GMS and patients' survival was investigated. Then the relationship between GMS and mismatch repair (MMR) status, Epstein-Barr virus (EBV) infection were determined using immunohistochemistry (IHC) and in situ hybridization, and the expression of PD1/PD-L1 was examined...
February 8, 2017: Journal of Cancer Research and Clinical Oncology
https://www.readbyqxmd.com/read/28177621/complex-and-non-centrosymmetric-stacking-of-layered-metal-dichalcogenide-materials-created-by-screw-dislocations
#12
Melinda J Shearer, Leith Samad, Yi Zhang, Yuzhou Zhao, Alexander A Puretzky, Kevin W Eliceiri, John C Wright, Robert J Hamers, Song Jin
The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations...
February 8, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28170401/clinical-practice-of-analysis-of-anti-drug-antibodies-against-interferon-beta-and-natalizumab-in-multiple-sclerosis-patients-in-europe-a-descriptive-study-of-test-results
#13
Jenny Link, Ryan Ramanujam, Michael Auer, Malin Ryner, Signe Hässler, Delphine Bachelet, Cyprien Mbogning, Clemens Warnke, Dorothea Buck, Poul Erik Hyldgaard Jensen, Claudia Sievers, Kathleen Ingenhoven, Nicolas Fissolo, Raija Lindberg, Verena Grummel, Naoimh Donnellan, Manuel Comabella, Xavier Montalban, Bernd Kieseier, Per Soelberg Sørensen, Hans-Peter Hartung, Tobias Derfuss, Andy Lawton, Dan Sikkema, Marc Pallardy, Bernhard Hemmer, Florian Deisenhammer, Philippe Broët, Pierre Dönnes, Julie Davidson, Anna Fogdell-Hahn
Antibodies against biopharmaceuticals (anti-drug antibodies, ADA) have been a well-integrated part of the clinical care of multiple sclerosis (MS) in several European countries. ADA data generated in Europe during the more than 10 years of ADA monitoring in MS patients treated with interferon beta (IFNβ) and natalizumab have been pooled and characterized through collaboration within a European consortium. The aim of this study was to report on the clinical practice of ADA testing in Europe, considering the number of ADA tests performed and type of ADA assays used, and to determine the frequency of ADA testing against the different drug preparations in different countries...
2017: PloS One
https://www.readbyqxmd.com/read/28169534/water-stability-studies-of-hybrid-iodoargentates-containing-n-alkylated-or-n-protonated-structure-directing-agents-exploring-noncentrosymmetric-hybrid-structures
#14
Guang-Ning Liu, Xiao-Ming Jiang, Qing-Shun Fan, Muhammad Bilal Hussain, Ke Li, Hui Sun, Xin-Yu Li, Wan-Qing Liu, Cuncheng Li
In situ alkylation or protonation reactions on the thiazolyl-N donors of benzothiazole (btz) and its derivative 2-aminobenzothiazole (abtz) occurred to form four structure directing agents (SDAs), which feature different structure directing abilities and hydrophobicities. The thiazolyl-N alkylated and protonated btz cations direct to form an α-type (AgI2)(-) iodoargentate chain in (Etbtz)(AgI2) (1), (Prbtz)(AgI2) (2), and (Hbtz)(AgI2) (3), respectively, while the thiazolyl-N protonated abtz cation directs to form a new type of (Ag2I3)(-) anionic chain in (Habtz)(Ag2I3) (4)...
February 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28166758/stromal-alterations-in-ovarian-cancers-via-wavelength-dependent-second-harmonic-generation-microscopy-and-optical-scattering
#15
Karissa B Tilbury, Kirby R Campbell, Kevin W Eliceiri, Sana M Salih, Manish Patankar, Paul J Campagnola
BACKGROUND: Ovarian cancer remains the most deadly gynecological cancer with a poor aggregate survival rate; however, the specific rates are highly dependent on the stage of the disease upon diagnosis. Current screening and imaging tools are insufficient to detect early lesions and are not capable of differentiating the subtypes of ovarian cancer that may benefit from specific treatments. METHOD: As an alternative to current screening and imaging tools, we utilized wavelength dependent collagen-specific Second Harmonic Generation (SHG) imaging microscopy and optical scattering measurements to probe the structural differences in the extracellular matrix (ECM) of normal stroma, benign tumors, endometrioid tumors, and low and high-grade serous tumors...
February 6, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28165518/na2cdge2q6-q-s-se-two-metal-mixed-chalcogenides-with-phase-matching-abilities-and-large-second-harmonic-generation-responses
#16
Guang-Mao Li, Qiong Liu, Kui Wu, Zhi-Hua Yang, Shi-Lie Pan
In view of their inherent defects for commercial infrared nonlinear optical (IR NLO) materials, exploration for new IR NLO materials with excellent performance is an imperative and meaningful work. Herein, we report the successful design and synthesis of two metal-mixed chalcogenides containing divalent cations with d(10) electronic configuration: Na2CdGe2S6 and Na2CdGe2Se6. Both of them crystallize in the polar Cc space group and exhibit three-dimensional tunnel structures constructed by the CdQ4 tetrahedra and ∞[GeQ3]n chains with Na(+) located in the tunnels...
February 6, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28161576/molecular-assessment-of-collagen-denaturation-in-decellularized-tissues-using-a-collagen-hybridizing-peptide
#17
Jeongmin Hwang, Boi Hoa San, Neill J Turner, Lisa J White, Denver M Faulk, Stephen F Badylak, Yang Li, S Michael Yu
: Decellularized extracellular matrix (ECM) derived from tissues and organs are emerging as important scaffold materials for regenerative medicine. Many believe that preservation of the native ECM structure during decellularization is highly desirable. However, because effective techniques to assess the structural damage in ECM are lacking, the disruptive effects of a decellularization method and the impact of the associated structural damage upon the scaffold's regenerative capacity are often debated...
February 1, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28158081/radiation-force-of-a-high-energy-laser-and-its-effects-on-second-harmonic-generation
#18
Ruifeng Su, Haitao Liu, Yingchun Liang, Fuli Yu
The radiation force of a high-energy laser caused by reflection at the input surface of a mounted KH<sub>2</sub>PO<sub>4</sub> (KDP) crystal is studied, along with its effects on the second-harmonic generation (SHG) efficiency of the laser beam. A comprehensive model incorporating principles of momentum transfer, mechanics, and optics is proposed, taking advantage of which, the mechanical stress within the KDP crystal that is caused by the radiation force, and the SHG efficiency that is affected by the stress are successively studied...
February 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28157999/fully-resonant-tunable-monolithic-frequency-conversion-as-a-coherent-uva-source
#19
Joanna A Zielińska, Andrius Zukauskas, Carlota Canalias, Mehmet A Noyan, Morgan W Mitchell
We demonstrate a monolithic frequency converter incorporating up to four tuning degrees of freedom, three temperature and one strain, allowing resonance of pump and generated wavelengths simultaneous with optimal phase-matching. With a Rb-doped periodically-poled potassium titanyl phosphate (KTP) implementation, we demonstrate efficient continuous-wave second harmonic generation from 795 to 397, with low-power efficiency of 72% and high-power slope efficiency of 4.5%. The measured performance shows good agreement with theoretical modeling of the device...
January 23, 2017: Optics Express
https://www.readbyqxmd.com/read/28157906/phase-and-amplitude-regeneration-of-a-rectangular-8-qam-in-a-phase-sensitive-amplifier-with-low-order-harmonics
#20
Hongxiang Wang, Gen Li, Yuefeng Ji
A scheme of regenerating the rectangular 8-QAM with two amplitude and eight phase states is proposed. The scheme can highly improve the efficiency utilizing the fifth and the third harmonics, instead of the seventh harmonic, which is difficult to generate and necessary for the traditional regeneration scheme. By separating the regeneration process into two steps, the scheme can also realize the separation of the different level states and the reduction of the amplitude and phase noise. The improvement of the error vector magnitude and the variances of phase and amplitude show the effectiveness of the scheme for the rectangular 8-QAM signal regeneration...
January 20, 2017: Applied Optics
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