Generation and focusing of submilliwatt-average-power 50-nm pulses by the fifth harmonic of a KrF laser

Yoshitomi, Dai; Shimizu, Tadao; Sekikawa, Taro; Watanabe, S.

doi:10.1364/ol.27.002170

Cited by 30 publications

(15 citation statements)

References 25 publications

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“…1, [8][9][10] Both methods provide information on two-dimensional photon intensity distribution with a spatial resolution of 1 to 2 m. The possibility of applying these techniques to FELs is, however, limited. The FEL pulse energy levels of VUV and XUV radiation may be some orders of magnitude higher than those of HHG sources and can cause radiation damage on fluorescence screens and, in general, on any solid irradiated surface.…”

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confidence: 99%

Method based on atomic photoionization for spot-size measurement on focused soft x-ray free-electron laser beams

Sorokin

Gottwald

Hoehl

et al. 2006

Applied Physics Letters

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A method has been developed and applied to measure the beam waist and spot size of a focused soft x-ray beam at the free-electron laser FLASH of the Deutsches Elektronen-Synchrotron in Hamburg. The method is based on a saturation effect upon atomic photoionization and represents an indestructible tool for the characterization of powerful beams of ionizing electromagnetic radiation. At the microfocus beamline BL2 at FLASH, a full width at half maximum focus diameter of ͑15± 2͒ m was determined. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2397561͔ Recent progress in developing pulsed high-power vacuum ultraviolet ͑VUV͒ and soft x-ray uv ͑XUV͒ sources, such as higher-harmonic generation ͑HHG͒ sources 1 and free-electron lasers ͑FELs͒, 2 has opened the door to extended research on nonlinear interaction of electromagnetic radiation with matter from the optical region to shorter wavelengths. When focused into a spot of a few micrometers in diameter, the radiation can reach peak irradiance levels of more than 10 13 W cm −2 where nonlinear effects such as atomic multiphoton ionization occur. 3-6 A key point for the understanding and theoretical description of nonlinear processes is, in general, their dependence on irradiance. Therefore, among other quantities such as pulse energy and duration, spot-size determination of focused high-intensity VUV and XUV radiation is mandatory.Recently, two conventional methods have been applied to measure the spot size of focused HHG beams, namely, the knife-edge 7 and the fluorescence screen technique. 1,[8][9][10] Both methods provide information on two-dimensional photon intensity distribution with a spatial resolution of 1 to 2 m. The possibility of applying these techniques to FELs is, however, limited. The FEL pulse energy levels of VUV and XUV radiation may be some orders of magnitude higher than those of HHG sources and can cause radiation damage on fluorescence screens and, in general, on any solid irradiated surface. Moreover, due to its statistical nature, a beam of FEL radiation based on self-amplified spontaneous emission 2 may strongly fluctuate from shot to shot, perpendicular to the propagation axis, and requires spot-size measurements which do not depend on the beam position. In this context, we describe a method which has been used to determine the beam waist and spot size of a focused beam at the XUV-FEL facility FLASH of the Deutsches Elektronen-Synchrotron in Hamburg. 11 It is based on a saturation effect upon photoionization of a rare gas and manifests itself by a sublinear increase in the ion yield as a function of the photon number per pulse. It is due to a considerable reduction in the number of target atoms within the interaction zone by ionization with a single photon pulse and becomes stronger with decreasing beam cross section. The method is indestructible and not affected by fluctuations of the beam position. Moreover, it can easily be realized in any ionization chamber by introducing a ͑rare͒ gas and detecting the photoionization signal as a fun...

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mentioning

confidence: 99%

Method based on atomic photoionization for spot-size measurement on focused soft x-ray free-electron laser beams

Sorokin

Gottwald

Hoehl

et al. 2006

Applied Physics Letters

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“…The higher (7th) harmonics were reduced to the negligible level by the Sc=Si multilayer mirror designed for 49.6 nm. The fifth harmonic reflected by the f 20 cm multilayer mirror was focused into a diameter of 2 m [20]. The rare gases used for ionization were continuously supplied from a metal tube with a 0.7 mm inside diameter.…”

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confidence: 99%

“…We assumed the temporal Gaussian profile and the focusing of the Gaussian beam with M 2 12 [20]. The angular distribution of photoelectrons is expressed for 25 eV photons by [22] …”

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confidence: 99%

Observation of Two-Photon Above-Threshold Ionization of Rare Gases by xuv Harmonic Photons

et al. 2004

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We have successfully observed two-photon above-threshold ionization in rare gas atoms (Ar, Xe, and He) by the fifth harmonic (25 eV photon energy) of a KrF laser. Use of the energy-resolved photoelectron counting system together with our laser, providing strong 25 eV radiation at 40-100 Hz, enabled us to detect the very weak single-color two-photon above-threshold ionization signals. Experimental data are in good agreement with our theoretical calculations newly developed along the line of multichannel quantum defect theory.

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“…The first step towards this goal is to establish high-power multicolor ultrashort laser synchronization system. It is essential to generate synchronized multicolor pulses for intriguing applications in ultrafast science and technology, such as generation of coherent THz radiation [4], all-optical atomic clock [5], ultrafast fluorescence dynamics [6], coherent optical frequency transfer [7], high-order harmonic generation [8], [9], and so on. Great effort has been devoted to the improvement of laser synchronization accuracy and robustness.…”

Section: Introductionmentioning

confidence: 99%

Up to 85-W 1030-nm Fiber Laser Synchronized to 800- and 1550-nm Femtosecond Lasers at 79.5 MHz

Yang

Yan

et al. 2011

IEEE Photon. Technol. Lett.

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We achieved high-power synchronized multicolor ultrashort lasers by spectral fraction amplification and master-slave laser configuration at 79.5-MHz repetition rate. The amplified high-power laser pulses at 1030 nm were synchronous to 800-and 1550-nm laser pulses with the timing jitter of 7.7 and 56.5 fs, respectively. Synchronized frequency-doubled femtosecond green light with 16.7-W average power was obtained.Index Terms-Doped fiber amplifiers, fiber nonlinear optics.

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Generation and focusing of submilliwatt-average-power 50-nm pulses by the fifth harmonic of a KrF laser

Cited by 30 publications

References 25 publications

Method based on atomic photoionization for spot-size measurement on focused soft x-ray free-electron laser beams

Method based on atomic photoionization for spot-size measurement on focused soft x-ray free-electron laser beams

Observation of Two-Photon Above-Threshold Ionization of Rare Gases by xuv Harmonic Photons

Up to 85-W 1030-nm Fiber Laser Synchronized to 800- and 1550-nm Femtosecond Lasers at 79.5 MHz

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