Articles de revues : « Laser Molecular Interactions »

1

Boisseau, C., et J. Vigué. « Laser-dressed molecular interactions at long range ». Optics Communications 127, n^o 4-6 (juin 1996) : 251–56. http://dx.doi.org/10.1016/0030-4018(96)00105-8.

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2

Knight, Peter. « Chaos in Laser-Matter Interactions ». Journal of Modern Optics 35, n^o 5 (mai 1988) : 753. http://dx.doi.org/10.1080/09500348814550791.

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3

Marangos, J. P. « Fundamentals of Laser Interactions II ». Journal of Modern Optics 37, n^o 10 (octobre 1990) : 1687. http://dx.doi.org/10.1080/09500349014551881.

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4

Dong, Xiaomei, Yuhan Du, Miaohua Xu, Yutong Li, Zhe Zhang et Yingjun Li. « Effects of laser waveform on the generation of fast electrons in laser–solid interactions ». Chinese Optics Letters 21, n^o 6 (2023) : 063801. http://dx.doi.org/10.3788/col202321.063801.

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5

Lamprou, Theocharis, Rodrigo Lopez-Martens, Stefan Haessler, Ioannis Liontos, Subhendu Kahaly, Javier Rivera-Dean, Philipp Stammer et al. « Quantum-Optical Spectrometry in Relativistic Laser–Plasma Interactions Using the High-Harmonic Generation Process : A Proposal ». Photonics 8, n^o 6 (29 mai 2021) : 192. http://dx.doi.org/10.3390/photonics8060192.

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Quantum-optical spectrometry is a recently developed shot-to-shot photon correlation-based method, namely using a quantum spectrometer (QS), that has been used to reveal the quantum optical nature of intense laser–matter interactions and connect the research domains of quantum optics (QO) and strong laser-field physics (SLFP). The method provides the probability of absorbing photons from a driving laser field towards the generation of a strong laser–field interaction product, such as high-order harmonics. In this case, the harmonic spectrum is reflected in the photon number distribution of the infrared (IR) driving field after its interaction with the high harmonic generation medium. The method was implemented in non-relativistic interactions using high harmonics produced by the interaction of strong laser pulses with atoms and semiconductors. Very recently, it was used for the generation of non-classical light states in intense laser–atom interaction, building the basis for studies of quantum electrodynamics in strong laser-field physics and the development of a new class of non-classical light sources for applications in quantum technology. Here, after a brief introduction of the QS method, we will discuss how the QS can be applied in relativistic laser–plasma interactions and become the driving factor for initiating investigations on relativistic quantum electrodynamics.

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Zhang, Yong, Qiuyun Wang, Anmin Chen et Xun Gao. « Effect of laser pulse energy on atomic lines and molecular bands in femtosecond LIBS of aluminum ». Laser Physics 33, n^o 7 (18 mai 2023) : 076003. http://dx.doi.org/10.1088/1555-6611/acd4ad.

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Abstract This study explored the characteristics of atomic and molecular emissions in Al plasmas generated by femtosecond lasers. The influence of laser pulse energy on Al atoms and AlO molecules time-integrated spectra was examined. As laser pulse energy increased, the intensity of Al atoms increased, while the emission of AlO molecules first increased and then remained unchanged. Secondly, the vibration temperature of AlO was determined and found to result in strong emission at a low temperature. Finally, the influence of laser pulse energy on the time-resolved spectra of Al atom and AlO molecule was explored, finding consistency with the time-integrated emission. These results indicate that the Al atom and AlO molecule have different sensitivities to femtosecond laser pulse energy. This research enriches our knowledge of femtosecond laser-plasma interactions and has potential applications in material processing and spectroscopic analysis.

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Davies, W. S. « Laser interactions with matter ». Optics and Lasers in Engineering 26, n^o 1 (janvier 1997) : 72–73. http://dx.doi.org/10.1016/0143-8166(96)81157-2.

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Körmendi, F. F. « Kinematical relations at nonlinear laser field : Free electron interactions ». Laser and Particle Beams 8, n^o 3 (septembre 1990) : 451–59. http://dx.doi.org/10.1017/s0263034600008685.

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Kinematical relations of nonlinear interaction of laser beams with free charged particles are analyzed. General expressions are found for the number of scattered photons as a function of the number of simultaneously absorbed and/or emitted photons and the kinetic parameters of the charged particle-photon system. The results are applied to the processes of particle acceleration by lasers, frequency conversion, solitonic propagation, and others.

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9

Limpouch, J., L. Drska et R. Liska. « Fokker–Planck simulations of interactions of femtosecond laser pulses with dense plasmas ». Laser and Particle Beams 12, n^o 1 (mars 1994) : 101–10. http://dx.doi.org/10.1017/s0263034600007266.

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The interaction of femtosecond laser pulses with solid-state density plasmas in regime of normal skin effect is investigated by means of numerical simulation. For short-wavelength lasers and laser pulses with length ≲ 120 fs full width at half maximum, the regime of normal skin effect is shown to hold for peak intensities up to 1017 W/cm2. The basic characteristics of the interaction are revealed and certain departures from simplistic models in electron distribution function, in plasma dielectric constant, and in laser absorption are pointed out. Comparison with the published experimental results is made.

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BATANI, DIMITRI, SABRINA BIAVA, SERGIO BITTANTI et FABIO PREVIDI. « A cellular automaton model of laser–plasma interactions ». Laser and Particle Beams 19, n^o 4 (octobre 2001) : 631–42. http://dx.doi.org/10.1017/s0263034601194103.

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This paper deals with the realization of a CA model of the physical interactions occurring when high-power laser pulses are focused on plasma targets. The low-level and microscopic physical laws of interactions among the plasma and the photons in the pulse are described. In particular, electron–electron interaction via the Coulomb force and photon–electron interaction due to ponderomotive forces are considered. Moreover, the dependence on time and space of the index of refraction is taken into account, as a consequence of electron motion in the plasma. Ions are considered as a fixed background. Simulations of these interactions are provided in different conditions and the macroscopic dynamics of the system, in agreement with the experimental behavior, are evidenced.

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11

Key, M. H. « The Physics of Laser Plasma Interactions ». Journal of Modern Optics 36, n^o 3 (mars 1989) : 417–18. http://dx.doi.org/10.1080/09500348914550481.

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Shirakawa, Masayuki, Takayoshi Kobayashi et Eiji Tokunaga. « Solvent Effects in Highly Efficient Light-Induced Molecular Aggregation ». Applied Sciences 9, n^o 24 (9 décembre 2019) : 5381. http://dx.doi.org/10.3390/app9245381.

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It has been reported that when irradiated with laser light non-resonant with the main absorption peaks, porphyrin molecules (4-[10,15,20-tris(4-sulfophenyl)-21,24-dihydroporphyrin-5-yl]benzenesulfonic acid, TPPS) in an aqueous solution become 10,000 to 100,000 times more efficient in light-induced molecular aggregation than expected from the ratio of gradient force potential to the thermal energy of molecules at room temperature. To determine the mechanism of this phenomenon, experiments on the light-induced aggregation of TPPS in alcohol solutions (methanol, ethanol, and butanol) were performed. In these alcohol solutions, the absorbance change was orders of magnitude smaller than in the aqueous solution. Furthermore, it was found that the absorbance change in the aqueous solution tended to be saturated with the increase of the irradiation intensity, but in the ethanol solution, the absorbance change increased linearly. These results can be qualitatively explained by the model in which intermolecular light-induced interactions between molecules within a close distance among randomly distributed molecules in the laser irradiation volume are highly relevant to the signal intensity. However, conventional dipole–dipole interactions, such as the Keesom interaction, are not quantitatively consistent with the results.

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De Moor, Roeland Jozef Gentil, Jeroen Verheyen, Peter Verheyen, Andrii Diachuk, Maarten August Meire, Peter Jozef De Coster, Mieke De Bruyne et Filip Keulemans. « Laser Teeth Bleaching : Evaluation of Eventual Side Effects on Enamel and the Pulp and the Efficiency In Vitro and In Vivo ». Scientific World Journal 2015 (2015) : 1–12. http://dx.doi.org/10.1155/2015/835405.

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Light and heat increase the reactivity of hydrogen peroxide. There is no evidence that light activation (power bleaching with high-intensity light) results in a more effective bleaching with a longer lasting effect with high concentrated hydrogen peroxide bleaching gels. Laser light differs from conventional light as it requires a laser-target interaction. The interaction takes place in the first instance in the bleaching gel. The second interaction has to be induced in the tooth, more specifically in the dentine. There is evidence that interaction exists with the bleaching gel: photothermal, photocatalytical, and photochemical interactions are described. The reactivity of the gel is increased by adding photocatalyst of photosensitizers. Direct and effective photobleaching, that is, a direct interaction with the colour molecules in the dentine, however, is only possible with the argon (488 and 415 nm) and KTP laser (532 nm). A number of risks have been described such as heat generation. Nd:YAG and especially high power diode lasers present a risk with intrapulpal temperature elevation up to 22°C. Hypersensitivity is regularly encountered, being it of temporary occurrence except for a number of diode wavelengths and the Nd:YAG. The tooth surface remains intact after laser bleaching. At present, KTP laser is the most efficient dental bleaching wavelength.

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Micheau, S., F. A. Gutierrez, B. Pons et H. Jouin. « Screening models for laser–cluster interactions ». Journal of Physics B : Atomic, Molecular and Optical Physics 38, n^o 18 (5 septembre 2005) : 3405–22. http://dx.doi.org/10.1088/0953-4075/38/18/011.

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Gao, Ju, et Fang Shen. « Ponderomotive tunnelling in electron–laser interactions ». Journal of Physics B : Atomic, Molecular and Optical Physics 40, n^o 14 (6 juillet 2007) : F215—F222. http://dx.doi.org/10.1088/0953-4075/40/14/f01.

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Korani, Youssef, et Hassan Sabzyan. « Spin dynamics in HeH2+ molecular ion in intense laser fields ». Physical Chemistry Chemical Physics 18, n^o 46 (2016) : 31606–21. http://dx.doi.org/10.1039/c6cp05455b.

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A theoretical study is carried out on the effect of non-dipole interactions on the electron spin dynamics in the asymmetric diatomic HeH²⁺ in its first excited state in intense linearly polarized laser fields.

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17

Jackson, William M. « Tunable Ultraviolet Laser Studies of Photon-Molecular Interactions of Cometary Interest ». Symposium - International Astronomical Union 120 (1987) : 67–73. http://dx.doi.org/10.1017/s007418090015380x.

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Most of the cometary radicals are thought to be formed in the coma by photodissociation processes. Successful modeling of the coma requires a detailed knowledge of the products that are formed from the various parent molecules, and the energy partitioning among these products. This information has to be obtained as a function of wavelength, because the Sun is not a monochromatic source. in this review, the status of the experimental knowledge of some key molecules will be discussed, along with the prospects of some new laboratory techniques that can fill in the gaps in our present knowledge.

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Dromey, B., C. Bellei, D. C. Carroll, R. J. Clarke, J. S. Green, S. Kar, S. Kneip et al. « Third harmonic order imaging as a focal spot diagnostic for high intensity laser-solid interactions ». Laser and Particle Beams 27, n^o 2 (12 mars 2009) : 243–48. http://dx.doi.org/10.1017/s0263034609000329.

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AbstractAs the state of the art for high power laser systems increases from terawatt to petawatt level and beyond, a crucial parameter for routinely monitoring high intensity performance is laser spot size on a solid target during an intense interaction in the tight focus regime (<10 µm). Here we present a novel, simple technique for characterizing the spatial profile of such a laser focal spot by imaging the interaction region in third harmonic order (3ωlaser). Nearly linear intensity dependence of 3ωlaser generation for interactions >1019 Wcm−2 is demonstrated experimentally and shown to provide the basis for an effective focus diagnostic. Importantly, this technique is also shown to allow in-situ diagnosis of focal spot quality achieved after reflection from a double plasma mirror setup for very intense high contrast interactions (>1020 Wcm−2) an important application for the field of high laser contrast interaction science.

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Harding, S. E. « Mucoadhesive interactions ». Biochemical Society Transactions 31, n^o 5 (1 octobre 2003) : 1036–41. http://dx.doi.org/10.1042/bst0311036.

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The adhesive properties of certain types of biopolymer can be used to increase the residence time of orally or nasally administered drugs. A fuller understanding of the molecular processes underpinning such ‘mucoadhesive’ phenomena will help in the optimal design of delivery systems. The interactions involved are, however, less well defined compared with those often encountered in protein-recognition phenomena: mucoadhesive interaction products can be very large and polydisperse, so to probe them we need to adopt a different strategy to those used by protein biochemists. Reviewed herein is some of the recent work at physiological or near-physiological solution conditions involving molecular hydrodynamics – with analytical ultracentrifugation and SEC-MALLs (size-exclusion chromatography coupled to multi-angle laser light scattering) as the cornerstones – reinforced by viscometry and the imaging probes of electron microscopy and atomic force microscopy. These clearly demonstrate the mucoadhesive properties of both an unusual cationic protein [Deacon, Davis, Waite and Harding (1998) Biochemistry 37, 14108–14112] and more significantly chitosan polysaccharides of varying degrees of charge/acetylation as a function of solution conditions, and are providing the platform for the construction of stable formulations.

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Miles, Richard B., James B. Michael, Christopher M. Limbach, Sean D. McGuire, Tat Loon Chng, Matthew R. Edwards, Nicholas J. DeLuca, Mikhail N. Shneider et Arthur Dogariu. « New diagnostic methods for laser plasma- and microwave-enhanced combustion ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 373, n^o 2048 (13 août 2015) : 20140338. http://dx.doi.org/10.1098/rsta.2014.0338.

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The study of pulsed laser- and microwave-induced plasma interactions with atmospheric and higher pressure combusting gases requires rapid diagnostic methods that are capable of determining the mechanisms by which these interactions are taking place. New rapid diagnostics are presented here extending the capabilities of Rayleigh and Thomson scattering and resonance-enhanced multi-photon ionization (REMPI) detection and introducing femtosecond laser-induced velocity and temperature profile imaging. Spectrally filtered Rayleigh scattering provides a method for the planar imaging of temperature fields for constant pressure interactions and line imaging of velocity, temperature and density profiles. Depolarization of Rayleigh scattering provides a measure of the dissociation fraction, and multi-wavelength line imaging enables the separation of Thomson scattering from Rayleigh scattering. Radar REMPI takes advantage of high-frequency microwave scattering from the region of laser-selected species ionization to extend REMPI to atmospheric pressures and implement it as a stand-off detection method for atomic and molecular species in combusting environments. Femtosecond laser electronic excitation tagging (FLEET) generates highly excited molecular species and dissociation through the focal zone of the laser. The prompt fluorescence from excited molecular species yields temperature profiles, and the delayed fluorescence from recombining atomic fragments yields velocity profiles.

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Joachain, C. J., et N. J. Kylstra. « Relativistic Effects in Laser–Atom Interactions ». Physica Scripta 68, n^o 3 (1 janvier 2003) : C72—C75. http://dx.doi.org/10.1238/physica.regular.068ac0072.

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Barber, Sam K. « Plasma interactions with bespoke laser pulses ». Nature Photonics 17, n^o 4 (avril 2023) : 295–96. http://dx.doi.org/10.1038/s41566-023-01179-z.

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Kwok, H. S., T. M. Rossi, W. S. Lau et D. T. Shaw. « Enhanced transmission in CO_2-laser-aerosol interactions ». Optics Letters 13, n^o 3 (1 mars 1988) : 192. http://dx.doi.org/10.1364/ol.13.000192.

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Chitanvis, Shirish M. « High energy laser interactions with water droplets ». Applied Optics 24, n^o 21 (1 novembre 1985) : 3552. http://dx.doi.org/10.1364/ao.24.003552.

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Boley, Charles D., et Alexander M. Rubenchik. « Modeling of laser interactions with composite materials ». Applied Optics 52, n^o 14 (7 mai 2013) : 3329. http://dx.doi.org/10.1364/ao.52.003329.

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Li, Bei, et Chee How Wong. « Molecular Dynamics Simulation of Lubricant Depletion Instability under Laser Heating ». Defect and Diffusion Forum 362 (avril 2015) : 23–28. http://dx.doi.org/10.4028/www.scientific.net/ddf.362.23.

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In this work, the coarse-grained molecular dynamics simulation is employed to study lubricant evolution and depletion when subjected to a moving laser heat source. A layered film structure is formed in the equilibrium lubricant system due to the polar interactions of the lubricant functional end groups with the disk substrate. The lubricant surface morphology and depletion profiles during laser heating are studied. It is shown that the lubricant undergoes severe depletion increasing as the laser heats up with time, resulting in aggravated lubricant diffusion and evaporation. Moreover, the surface temperature profile is examined under a moving laser heat source and it reveals that the increased temperature is centered around the laser beam and quickly decays away from the laser beam. The non-uniform temperature is formed due to heat transfer between heated beads and surrounding beads, which leads to non-uniformity of surface tension and thermocapillary stress, thereby depleting the lubricant away from the scanning laser beam on the disk surface.

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Zhong, Ming, Yanqiang Zhang, Xi Yang, Yufeng Yao, Junlong Guo, Yaping Wang et Yaxin Liu. « Assistive Grasping Based on Laser-point Detection with Application to Wheelchair-mounted Robotic Arms ». Sensors 19, n^o 2 (14 janvier 2019) : 303. http://dx.doi.org/10.3390/s19020303.

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As the aging of the population becomes more severe, wheelchair-mounted robotic arms (WMRAs) are gaining an increased amount of attention. Laser pointer interactions are an attractive method enabling humans to unambiguously point out objects and pick them up. In addition, they bring about a greater sense of participation in the interaction process as an intuitive interaction mode. However, the issue of human–robot interactions remains to be properly tackled, and traditional laser point interactions still suffer from poor real-time performance and low accuracy amid dynamic backgrounds. In this study, combined with an advanced laser point detection method and an improved pose estimation algorithm, a laser pointer is used to facilitate the interactions between humans and a WMRA in an indoor environment. Assistive grasping using a laser selection consists of two key steps. In the first step, the images captured using an RGB-D camera are pre-processed, and then fed to a convolutional neural network (CNN) to determine the 2D coordinates of the laser point and objects within the image. Meanwhile, the centroid coordinates of the selected object are also obtained using the depth information. In this way, the object to be picked up and its location are determined. The experimental results show that the laser point can be detected with almost 100% accuracy in a complex environment. In the second step, a compound pose-estimation algorithm aiming at a sparse use of multi-view templates is applied, which consists of both coarse- and precise-matching of the target to the template objects, greatly improving the grasping performance. The proposed algorithms were implemented on a Kinova Jaco robotic arm, and the experimental results demonstrate their effectiveness. Compared with commonly accepted methods, the time consumption of the pose generation can be reduced from 5.36 to 4.43 s, and synchronously, the pose estimation error is significantly improved from 21.31% to 3.91%.

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BAUER, D. « Plasma formation through field ionization in intense laser–matter interaction ». Laser and Particle Beams 21, n^o 4 (octobre 2003) : 489–95. http://dx.doi.org/10.1017/s0263034603214026.

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Optical field ionization is the earliest and fastest plasma-generating process during the interaction of intense laser light with matter. By using short and rapidly rising laser pulses, the free electron density may turn from being transparent for an incoming laser pulse to reflective in less than half a laser cycle, that is, on a subfemtosecond timescale. Extremely nonlinear optical effects arise as a consequence of this. In this article, the basics of optical field ionization that are relevant in analytical or numerical studies of intense laser–matter interactions are reviewed. Several macroscopic effects of field ionization in the interaction of intense laser pulses with solid targets are briefly surveyed.

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Li, Qianni, Xinrong Xu, Yanbo Wu, Debin Zou, Yan Yin et Tongpu Yu. « Generation of single circularly polarized attosecond pulses from near-critical density plasma irradiated by a two-color co-rotating circularly polarized laser ». Optics Express 30, n^o 22 (13 octobre 2022) : 40063. http://dx.doi.org/10.1364/oe.472982.

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In this paper, a new method is proposed to efficiently generate a single intense attosecond pulse with circular polarization (CP) through the interaction of an intense driving laser with a near-critical density plasma target. The driving laser is composed of two co-rotating CP lasers with similar frequencies but different pulse widths. When the matching condition is satisfied, the combined field is modulated to a short intense pulse followed by a weak tail. The resulting laser falling edge becomes steeper than the initial sub-pulses, which induces a quick one-time oscillation of the target surface. Meanwhile, the tail guarantees the energy to be compressed simultaneously in both polarization directions to the same extent, so that a single CP attosecond pulse can be produced efficiently and robustly via our method, which has been confirmed through extensive numerical simulations. In addition, our method makes it possible to generate a single CP attosecond pulse even for multi-cycle pulses that are already available for existing laser systems. This provides a novel way to advance the investigation of chiral-sensitive light-matter interactions in attosecond scales.

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Vinciguerra, Riccardo, Alfredo Borgia, Costanza Tredici et Paolo Vinciguerra. « Excimer laser tissue interactions in the cornea ». Experimental Eye Research 206 (mai 2021) : 108537. http://dx.doi.org/10.1016/j.exer.2021.108537.

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Psikal, J., O. Klimo et J. Limpouch. « Simulations of femtosecond laser pulse interaction with spray target ». Laser and Particle Beams 32, n^o 1 (28 janvier 2014) : 145–56. http://dx.doi.org/10.1017/s0263034614000032.

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AbstractLaser interactions with spray targets (clouds of submicron droplets) are studied here via numerical simulations using two-dimensional particle-in-cell codes. Our simulations demonstrate an efficient absorption of laser pulse energy inside the spray. The energy absorption efficiency depends on the inter-droplet distance, size of the cloud of droplets, and laser pulse intensity, as well as on the pre-evaporation of droplets due to laser pulse pedestal. We investigate in detail proton acceleration from the spray. Energy spectra of protons in various acceleration directions vary significantly depending on the density profile of the plasma created from the droplets and on laser intensity. The spray target can be alternative of foil targets for high intensity high repetition ultrahigh contrast femtosecond lasers. However, at intensities >1021 W/cm2, the efficiency of laser absorption and ion acceleration from the droplets drops significantly in contrast to foils.

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Renner, O., R. Liska et F. B. Rosmej. « Laser-produced plasma-wall interaction ». Laser and Particle Beams 27, n^o 4 (décembre 2009) : 725–31. http://dx.doi.org/10.1017/s0263034609990504.

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AbstractJets of laser–generated plasma represent a flexible and well-defined model environment for investigation of plasma interactions with solid surfaces (walls). The pilot experiments carried out on the iodine laser system (5–200 J, 0.44 µm, 0.25–0.3 ns, <1×1016 W/cm2) at the PALS Research Centre in Prague are reported. Modification of macroscopic characteristics of the Al plasma jets produced at laser-irradiated double-foil Al/Mg targets is studied by high-resolution, high-dispersion X-ray spectroscopy. The spatially variable, complex satellite structure observed in emission spectra of the Al Lyα group proves a formation of rather cold dense plasma at the laser-exploded Al foil, an occurrence of the hot plasma between both foils and subsequent thermalization, deceleration and trapping of Al ions in the colliding plasma close to the Mg foil surface. The spectra interpretation based on the collisional-radiative code is complemented by 1D and 2D hydrodynamic modeling of the plasma expansion and interaction of counter-propagating Al/Mg plasmas. The obtained results demonstrate a potential of high resolution X-ray diagnostics in investigation of the laser-produced plasma–wall interactions.

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NAKAJIMA, KAZUHISA. « Particle acceleration by ultraintense laser interactions with beams and plasmas ». Laser and Particle Beams 18, n^o 3 (juillet 2000) : 519–28. http://dx.doi.org/10.1017/s0263034600183247.

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Recently, there has been great interest growing in ultrahigh field particle acceleration driven by ultraintense laser interactions with beams and plasmas. Although numerous concepts of particle acceleration by laser fields have been proposed almost since the beginning of the laser evolution, there has been tremendous progress in recent years on their theoretical and experimental aspects owing to advances in the generation of ultraintense short laser pulses. The laser–plasma accelerator concepts are reviewed on the laser wakefield acceleration mechanism. In particular, the electron acceleration by the laser wakefield in plasmas is illustrated by our recent experimental results, including the propagation of the ultrashort intense laser pulses in plasmas.

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Maurya, Sandeep Kumar, Dhiman Das et Debabrata Goswami. « Probing Intermolecular Interactions in Binary Liquid Mixtures Using Femtosecond Laser-Induced Self-Defocusing ». Applied Spectroscopy 70, n^o 10 (20 juillet 2016) : 1655–61. http://dx.doi.org/10.1177/0003702816643547.

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Photothermal behavior of binary liquid mixtures has been studied using a high repetition rate (HRR) Z-scan technique with femtosecond laser pulses. Changes in the peak–valley difference in transmittance (ΔTP–V) for closed aperture Z-scan experiments are indicative of thermal effects induced by HRR femtosecond laser pulses. We show such indicative results can have a far-reaching impact on molecular properties and intermolecular interactions in binary liquid mixtures. Spectroscopic parameters derived from this experimental technique show that the combined effect of physical and molecular properties of the constituent binary liquids can be related to the components of the binary liquid.

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Zhu, Chengcheng, Hailing Wang, Ben Chen, Yini Chen, Tao Yang, Jianping Yin et Jinjun Liu. « Fine and hyperfine interactions of PbF studied by laser-induced fluorescence spectroscopy ». Journal of Chemical Physics 157, n^o 8 (28 août 2022) : 084307. http://dx.doi.org/10.1063/5.0099716.

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The fine and hyperfine interactions in PbF have been studied using the laser-induced fluorescence (LIF) spectroscopy method. Cold PbF molecular beam was produced by laser-ablating a Pb rod under jet-cooled conditions, followed by the reaction with SF6. The LIF excitation spectrum of the (0, 0) band in the B2Σ+– X2Π1/2 system of the 208PbF, 207PbF, and 206PbF isotopologues has been recorded with rotational, fine structure, and hyperfine-structure resolution. Transitions in the LIF spectrum were assigned and combined with the previous X2Π3/2– X2Π1/2 emission spectrum in the near-infrared region [Ziebarth et al., J. Mol. Spectrosc. 191, 108–116 (1998)] and the X2Π1/2 state pure rotational spectrum of PbF [Mawhorter et al., Phys. Rev. A 84, 022508 (2011)] in a global fit to derive the rotational, spin–orbit, spin–rotation, and hyperfine interaction parameters of the ground ( X2Π1/2) and the excited ( B2Σ+) electronic states. Molecular constants determined in the present work are compared with previously reported values. Particularly, the significance of the hyperfine parameters, A⊥ and A‖, of 207Pb is discussed.

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Drska, L., J. Limpouch et R. Liska. « Fokker-Planck simulations of ultrashort-pulse laser-plasma interactions ». Laser and Particle Beams 10, n^o 3 (septembre 1992) : 461–71. http://dx.doi.org/10.1017/s0263034600006704.

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The interaction of ultrashort laser pulses with a fully ionized plasma is investigated in the plane geometry by means of numerical simulation. The impact of the space oscillations in the amplitude of the laser electric field on the shape of the electron distribution function, on laser beam absorption, and on electron heat transport is demonstrated. Oscillations in the absorption rate of laser radiation with the minima coincident to the maxima of the laser electric field lead to a further decrease in the absorption of laser radiation. Heat flux in the direction of increasing temperature in the underdense region is caused by the modification of the electron distribution function and by the density gradient. A limitation of heat flux to the overdense plasma isobserved with the flux limiter in range 0.03–0.08, growing moderately with the intensity 1014–1016 W/cm2 of the incident 1.2-ps laser pulse.

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Wang Gui-Qiu et Wang You-Nian. « Influence of laser field on interactions between swift molecular ions and solids ». Acta Physica Sinica 52, n^o 4 (2003) : 939. http://dx.doi.org/10.7498/aps.52.939.

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Nangia, Shivangi, et Barbara J. Garrison. « Molecular dynamics simulations of matrix assisted laser desorption ionization : Matrix–analyte interactions ». Nuclear Instruments and Methods in Physics Research Section B : Beam Interactions with Materials and Atoms 269, n^o 14 (juillet 2011) : 1744–47. http://dx.doi.org/10.1016/j.nimb.2010.12.007.

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Dlott, Dana D. « Focus Fluctuations in Laser-Materials Interactions ». Optics and Photonics News 13, n^o 9 (1 septembre 2002) : 34. http://dx.doi.org/10.1364/opn.13.9.000034.

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Ponomarev, Yu N. « Photo-acoustic investigation of the interaction of laser radiation with molecules and inter-molecular interactions in gases ». Infrared Physics 32 (janvier 1991) : 377–84. http://dx.doi.org/10.1016/0020-0891(91)90126-z.

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Ivanova, Bojidarka, et Michael Spiteller. « Physical Properties and Molecular Conformations of Indole Alkaloids and Model Protein Interactions – Theoretical vs. Experimental Study ». Natural Product Communications 7, n^o 2 (février 2012) : 1934578X1200700. http://dx.doi.org/10.1177/1934578x1200700206.

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The physical properties and molecular structure of five natural indole alkaloids (IAs) and their interaction with protein targets have been studied, experimentally and theoretically. Electronic absorption (EAs) and CD spectroscopy, electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), as well as imaging mass spectrometric techniques (IMS) were used, analyzing the isolated alkaloids and corresponding IAs/protein molecular complexes. Theoretical quantum chemical DFT calculations were also applied. The mechanism of their biological activity and structure-activity relationship as potential neurologically active compounds were studied, using the model interactions with 5HT2A receptors. The gas-phase stable molecular fragments of the IAs are discussed comparing the experimental mass spectrometric data and theoretical quantum chemical DFT calculations of the different molecular fragments of the IAs.

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Mutskov, Vesco, Delphine Gerber, Dimitri Angelov, Juan Ausio, Jerry Workman et Stefan Dimitrov. « Persistent Interactions of Core Histone Tails with Nucleosomal DNA following Acetylation and Transcription Factor Binding ». Molecular and Cellular Biology 18, n^o 11 (1 novembre 1998) : 6293–304. http://dx.doi.org/10.1128/mcb.18.11.6293.

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ABSTRACT In this study, we examined the effect of acetylation of the NH2 tails of core histones on their binding to nucleosomal DNA in the absence or presence of bound transcription factors. To do this, we used a novel UV laser-induced protein-DNA cross-linking technique, combined with immunochemical and molecular biology approaches. Nucleosomes containing one or five GAL4 binding sites were reconstituted with hypoacetylated or hyperacetylated core histones. Within these reconstituted particles, UV laser-induced histone-DNA cross-linking was found to occur only via the nonstructured histone tails and thus presented a unique tool for studying histone tail interactions with nucleosomal DNA. Importantly, these studies demonstrated that the NH2 tails were not released from nucleosomal DNA upon histone acetylation, although some weakening of their interactions was observed at elevated ionic strengths. Moreover, the binding of up to five GAL4-AH dimers to nucleosomes occupying the central 90 bp occurred without displacement of the histone NH2 tails from DNA. GAL4-AH binding perturbed the interaction of each histone tail with nucleosomal DNA to different degrees. However, in all cases, greater than 50% of the interactions between the histone tails and DNA was retained upon GAL4-AH binding, even if the tails were highly acetylated. These data illustrate an interaction of acetylated or nonacetylated histone tails with DNA that persists in the presence of simultaneously bound transcription factors.

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Yang, Jinghui, Cuiying Huang et Xinping Zhang. « Femtosecond Optical Annealing Induced Polymer Melting and Formation of Solid Droplets ». Polymers 11, n^o 1 (13 janvier 2019) : 128. http://dx.doi.org/10.3390/polym11010128.

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Interaction between femtosecond laser pulses with polymeric thin films induced transient optical annealing of the polymer molecules. Melting of the polymer films took place during the transient annealing process, so that a solid-liquid-solid phase transition process was observed. Ultrafast cooling of the melting polymer produced solidified droplets. Microscopic and spectroscopic characterization revealed that the polymer molecules were rearranged with preferable H-aggregation to reach the lowest formation energy during the melting process. Intermolecular coupling was enhanced due to the modified molecular arrangement. This observation of melting of polymeric semiconductors due to the interaction with femtosecond light pulses is potentially important for better understanding laser-matter interactions and for exploring organic optoelectronic devices through special material processing.

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Jonoska, N., et N. C. Seeman. « Molecular ping-pong Game of Life on a two-dimensional DNA origami array ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 373, n^o 2046 (28 juillet 2015) : 20140215. http://dx.doi.org/10.1098/rsta.2014.0215.

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We propose a design for programmed molecular interactions that continuously change molecular arrangements in a predesigned manner. We introduce a model where environmental control through laser illumination allows platform attachment/detachment oscillations between two floating molecular species. The platform is a two-dimensional DNA origami array of tiles decorated with strands that provide both, the floating molecular tiles to attach and to pass communicating signals to neighbouring array tiles. In particular, we show how algorithmic molecular interactions can control cyclic molecular arrangements by exhibiting a system that can simulate the dynamics similar to two-dimensional cellular automata on a DNA origami array platform.

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Cairns, R. A., B. Ersfeld, D. Johnson, D. C. McDonald et H. Ruhl. « Nonlinear Harmonic Response in Laser-Plasma Interactions ». Physica Scripta T75, n^o 1 (1998) : 99. http://dx.doi.org/10.1238/physica.topical.075a00099.

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Li, Chun, Guo-Qian Liao, Mu-Lin Zhou, Fei Du, Jing-Long Ma, Yu-Tong Li, Wei-Min Wang, Zheng-Ming Sheng, Li-Ming Chen et Jie Zhang. « Backward terahertz radiation from intense laser-solid interactions ». Optics Express 24, n^o 4 (18 février 2016) : 4010. http://dx.doi.org/10.1364/oe.24.004010.

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Chen, Min, Zheng-Ming Sheng, Jun Zheng, Yan-Yun Ma, Muhammad Bari, Yu-Tong Li et Jie Zhang. « Surface electron acceleration in relativistic laser-solid interactions ». Optics Express 14, n^o 7 (2006) : 3093. http://dx.doi.org/10.1364/oe.14.003093.

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Roy, V., M. Olivier et M. Piché. « Pulse interactions in the stretched-pulse fiber laser ». Optics Express 13, n^o 23 (2005) : 9217. http://dx.doi.org/10.1364/opex.13.009217.

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Galushkin, M. G., E. B. Gordon, M. S. Drozdov et K. A. Sviridov. « Chemical Intensification of Nonlinear Multi-Wave Interactions ». Laser Chemistry 12, n^o 3-4 (1 janvier 1992) : 199–209. http://dx.doi.org/10.1155/lc.12.199.

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Nonlinear interaction of laser emission with a chemically reactive medium, in which a branched chain reaction may readily occur, has been analyzed aiming at essential intensification the contrast of photochemically induced phase gratings. For the model system CS2/O2, the degenerated four-wave mixing is theoretically studied under the assumption of CS2 photodissociation followed by subsequent secondary reactions induced by reactive photodissociation products. For varied CS2 concentrations and incident flux intensities, the dynamics of nonlinear reflection has been analyzed and same laser applications of such systems are suggested.

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KRUSHELNICK, K., E. CLARK, Z. NAJMUDIN, M. SALVATI, M. I. K. SANTALA, M. TATARAKIS, A. E. DANGOR et al. « Diagnosis of peak laser intensity from high-energy ion measurements during intense laser interactions with underdense plasmas ». Laser and Particle Beams 18, n^o 4 (octobre 2000) : 595–600. http://dx.doi.org/10.1017/s0263034600184034.

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Experiments were performed using high-power laser pulses (greater than 50 TW) focused into underdense helium, neon, or deuterium plasmas (ne ≤ 5 × 1019 cm−3). Ions having energies greater than 300 keV were measured to be produced primarily at 90° to the axis of laser propagation. Ion energies greater than 6 MeV were recorded from interactions with neon. Spatially resolved pinhole images of the ion emission were also obtained and were used to estimate the intensity of the focused radiation in the interaction region.

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