共查询到20条相似文献,搜索用时 15 毫秒
1.
Ishii N Adachi S Nomura Y Kosuge A Kobayashi Y Kanai T Itatani J Watanabe S 《Optics letters》2012,37(1):97-99
Multimillijoule, few-cycle, carrier-envelope-phase (CEP)-locked, near-IR pulses at 750 nm from an optical parametric chirped-pulse amplifier are applied to the generation of CEP-dependent, soft x-ray high harmonics around the boron K-edge at 188 eV. The dependence on the CEP manifests the phase coherence of high harmonics preserved in the highest-photon energy ever reported. Multimillijoule optical pulses also allow the extension of the cutoff energy up to 325 eV, exceeding the carbon K-edge of the water window. However, in this spectral range, the CEP dependence of harmonic spectra is not observed, suggesting the degradation of temporal coherence due to the heavy ionization of helium atoms. 相似文献
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Yi-De Chuang John Pepper Zahid Hussain Phil Batson M. Zahid Hasan 《Journal of Physics and Chemistry of Solids》2005,66(12):2173-2178
The progress of valence electronic spectroscopy with X-rays has been largely limited by the challenge of fine instrumentation. Relatively weak scattering cross-section and/or limited (coarse) energy resolution restrict X-ray spectroscopy to address fundamental issues in condensed-matter electron physics. Depending on the nature of excitations, high brightness photon beam from third-generation synchrotron facilities helps raise the count rates to a detectable limit over the noise level. Over the past decade, it has been realized that high-resolution resonant inelastic soft X-ray scattering has the potential to play an important role in understanding complex phenomena observed in highly correlated systems. Driven by such demand, we have developed a soft X-ray emission spectrograph based on variable line spacing (VLS) gratings to work in the soft X-ray and deep UV (the M edge of transition metals) regime. The slit-less design coupled with high quality optical elements and a high quantum efficiency (QE) in-vacuum CCD detector greatly improves the overall throughput. The M edge spectrograph has been demonstrated to have a resolving power better than 10,000 and will be used in conjunction with meV-resolution beamline (MERLIN) at the Advanced Light Source at Lawrence Berkeley National Laboratory. 相似文献
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We report on a soft x-ray microscope using a gas-discharge plasma with pseudo spark-like electrode geometry as a light source. The source produces a radiant intensity of 4 x 10(13) photons/(sr pulse) for the 2.88 nm emission line of helium-like nitrogen. At a demonstrated 1 kHz repetition rate a brilliance of 4.3 x 10(9) photons/(microm2 sr s) is obtained for the 2.88 nm line. Ray-tracing simulations show that, employing an adequate grazing incidence collector, a photon flux of 1 x 10(7) photons/(microm2 s) can be achieved with the current source. The applicability of the presented pinch plasma concept to soft x-ray microscopy is demonstrated in a proof-of-principle experiment. 相似文献
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The characteristics and applicability of the absorption spectroscopy system using the coherent transition radiation light source have been investigated. The configurations of the system are relatively simple. The operational conditions of an electron linear accelerator have been evaluated. The stability of the light intensity has been within ±2–3% in a wavenumber range of 4–13 cm−1. The light intensity has been found to be more than six orders of magnitude higher than that for the lowest limit for detection. 相似文献
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A feasible and convenient method is proposed to suppress higher-harmonics for a varied-line-spacing plane grating monochromator in the soft X-ray region. Related calculations and experiments demonstrate that decreasing the included angle slightly by changing the parameter of the exit arm length can significantly improve light purity. This method is suitable and has been used for experiments of detector calibration in beamline 4B7B at the Beijing Synchrotron Radiation Facility (BSRF). 相似文献
7.
R. W. Schoenlein A. H. Chin H. H. W. Chong R. W. Falcone T. E. Glover P. A. Heimann 《Synchrotron Radiation News》2013,26(1):20-27
On May 19, 2004, 250 guests from all over the world joined the DESY research center to celebrate 40 years of research with synchrotron radiation at DESY in Hamburg. “The first measurements with the light beam from the DESY ring accelerator started in 1964. DESY was one of the seed laboratories in which the worldwide success story of research with synchrotron radiation began,” Albrecht Wagner, chairman of the DESY Board of Directors, explained in his welcoming address. “Today, more than 1,900 scientists from 31 countries come to DESY every year to carry out experiments with synchrotron radiation.” Forty years ago, synchrotron radiation at DESY started from scratch. At the beginning of the 1960s, the radiation generated by the electrons in the bending magnets of their new 6 GeV electron synchrotron was regarded by DESY particle physicists as an unwanted, disruptive effect. 相似文献
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Zakaullah M. Alamgir K. Shafiq M. Sharif M. Waheed A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2002,30(6):2089-2094
The X-radiation emission from a low energy plasma focus with argon as a filling gas is investigated. Specifically, the attention is paid to determine the system efficiency for argon K-lines and Cu-K/sub /spl alpha// line emission at different filling pressures, and identify the radiation emission region. The highest argon line emission found at 1.5 mbar is about 30 mJ and the corresponding efficiency is 0.0015%. The same pressure is suitable for high Cu-K/sub /spl alpha// emission, which is about 70 mJ in 4/spl pi/ geometry and the system efficiency is 0.003%. The bulk of X-radiation is emitted from the region close to the anode tip, whereas some radiation emission takes place from the formed hot spots along the focus axis. These radiations are found suitable for backlighting in Al (1-1.56 keV) and Ti (2.9-4.96 keV) energy transmission bands. 相似文献
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Goulielmakis E Koehler S Reiter B Schultze M Verhoef AJ Serebryannikov EE Zheltikov AM Krausz F 《Optics letters》2008,33(13):1407-1409
Self-channeling of few-cycle laser pulses in helium at high pressure generates coherent light supercontinua spanning the range of 270-1000 nm, with the highest efficiency demonstrated to date. Our results open the door to the synthesis of powerful light waveforms shaped within the carrier field oscillation cycle and hold promise for the generation of pulses at the single-cycle limit. 相似文献
13.
S. V. Salikhov F. N. Chukhovskii A. M. Polyakov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(5):887-899
A solution of the problem of X-ray specular reflection from a statistically rough surface is presented. It is based on using
the Green function formalism. The Kirchhoff formula is used to describe the transmission of the wave field through a rough
interface. Generally, microscopically exact expressions for the coefficients of transmission through a rough surface and reflection
from it are obtained by taking multiple scattering effects into account. Averaging of the obtained expressions over possible
realizations of random roughness of the interface between media allows to obtain rigorous expressions for specular reflection
and transmission coefficients. The behavior of exact solutions in the limiting case of infinite correlation lengths is studied.
It is shown that, in this case, the obtained solution corresponds to the Debye-Waller normalization. Expressions for the reflection
and transmission coefficients making it possible to carry out numerical calculations are obtained in the Bourret approximation
of multiple-scattering theory. 相似文献
14.
R. H?rlein S. G. Rykovanov B. Dromey Y. Nomura D. Adams M. Geissler M. Zepf F. Krausz G. D. Tsakiris 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(2):475-481
Harmonic generation from relativistically oscillating plasma surfaces formed during the interaction of high contrast lasers
with solid-density
targets has been shown to be an efficient source of extreme ultraviolet (XUV) and X-ray radiation. Recent work has demonstrated
that the exceptional
coherence properties of the driving laser can be mirrored in the emitted radiation, permitting diffraction limited performance
and attosecond phase
locking of the harmonic radiation. These unique properties may allow the coherent harmonic focusing (CHF) of high harmonics
generated from solid
density targets to intensities on the order of the Schwinger limit of 1029 W cm-2 with laser systems available in the near future [Phys. Rev. Lett. 93, 115002 (2004)] and thus pave the way for unique experiments exploring the nonlinear
properties of vacuum on ultra-fast timescales. In this paper we investigate experimentally as well as numerically the prospect
of focusing high
harmonics under realistic experimental conditions and demonstrate, using particle in cell (PIC) simulations, that precise
control of the wavefronts
and thus the focusability of the generated harmonics is possible with pre-shaped targets. 相似文献
15.
Md. Monirul Haque Hironari Yamada Ahsa Moon Mami Yamada 《Journal of synchrotron radiation》2009,16(2):299-306
The performance of the far‐infrared (FIR) beamline of the 6 MeV tabletop synchrotron light source MIRRORCLE‐6FIR dedicated to far‐infrared spectroscopy is presented. MIRRORCLE‐6FIR is equipped with a perfectly circular optical system (PhSR) placed around the 1 m‐long circumference electron orbit. To illustrate the facility of this light source, the FIR output as well as its spectra were measured. The optimum optical system was designed by using the ray‐tracing simulation code ZEMAX. The measured FIR intensity with the PhSR in place is about five times higher than that without the PhSR, which is in good agreement with the simulation results. The MIRRORCLE‐6FIR spectral flux is compared with a standard thermal source and is found to be 1000 times greater than that from a typical thermal source at ~15 cm?1. It is also observed that the MIRRORCLE‐6FIR radiation has a highly coherent nature. The broadband infrared allows the facility to reach the spectral range from 10 cm?1 to 100 cm?1. MIRRORCLE‐6FIR, owing to a large beam current, the PhSR mirror system, a large dynamic aperture and small ring energy, can deliver a bright flux of photons in the FIR/THz region useful for broadband spectroscopy. 相似文献
16.
激光等离子体软X光源8—20nm光谱辐射研究 总被引:1,自引:0,他引:1
郭玉彬 《光谱学与光谱分析》1998,18(3):265-268
研制了了一种脉冲重复频率为10Hz的激光等离子软X射线源;傅波长0.53μm和波长1.06μm的激光脉冲,聚焦在不同的金属靶上,使之离子化。 相似文献
17.
Galina A. Vergunova Sergey Yu. Gus’kov Vladislav B. Rozanov Olga N. Rozmej 《Journal of Russian Laser Research》2010,31(5):509-518
We investigate theoretically the formation of a plasma in a plane layer of polymer foam (density ρ = 0.002 g/cm3 and thickness 800 μm) under the action of an external source of soft X-ray radiation under the conditions of PHELIX experiments. The incident
flux is assumed to have a Planck’s distribution over the spectrum with T
rad = 20–40 eV. In numerical calculations, the flux of incident X-ray radiation and the spectral constants of the target substance
are varied. The action of an external X-ray radiation source on a low-density foam substance with a density of 2 mg/cm3 causes a plasma to be formed with relatively homogeneous profiles of density and temperature T = 15–35 eV. Absorption of externalradiation energy is distributed in the volume. The plasma temperature increases with increase
in the external energy, and the energy passed through the plasma also increases. The results prove to be sensitive to the
values of optical constants used in numeral simulation. The spectral flux of external radiation passed through the plasma
is chosen as a criterion of correctness of the optical constants used in the calculations. In future experiments using the
PHELIX facility, we plan to investigate the slowing-down of an ion beam in a plasma formed as a result of indirect heating
of low-density polymer triacetate cellulose (TAC) foam with densities ρ = 0.001–0.01 g/cm3 under the action of a pulse of X-ray radiation, into which the laser radiation is preliminarily transformed. 相似文献
18.
We developed a deep-UV single-mode coherent light source through two-stage highly efficient frequency conversions by use of external cavities. In the first stage, second-harmonic power of 500 mW was obtained by frequency doubling of a 746-nm Ti:sapphire laser with a conversion efficiency of 40%. In the second stage, 50-mW power at ~252nm was obtained by doubly resonant sum-frequency mixing of 373-nm light from the first-stage conversion and 780-nm light from a diode laser. The output performance of this deep-UV light source is sufficient for laser cooling of neutral silicon atoms. 相似文献
19.
An infra-red emission tunable down to 16 μm is produced by a hydrogen Stokes shifted dye laser. The peak power measured at 16 μm is of ca. 50 kW in 2 ns within a one millimeter diameter beam. The corresponding light flux of the order of 5 MW cm-2 could allow a multi-step vibrational excitation of molecules absorbing down to 16 μm. Simultaneous emissions from the laser and from the previous Stokes bands are available at: 0.76, 1.62, 2.09 μm with respective peak powers of 550, 50 and 20 MW. Spectral widths of 0.8 cm-1 and of ca. 7 × 10-2 cm-1 are obtained for the dye laser and for each of the Stokes band respectively. 相似文献
20.
A single-bunch beam has been generated using a developed high-speed avalanche-type pulser in KURRI-LINAC in order to lift restrictions of the spectral resolution in the spectroscopic study and the delay time in the time-resolved measurement. Both of the rise and fall times of the developed pulser are 110 ps. The observation of CTR has confirmed the single-bunch beam. The degree of impurity of single bunch has been estimated to be 1.5% by the analysis of the interferogram. 相似文献