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A S Pirozhkov,
M Kando,
T Zh Esirkepov,
P Gallegos,
H Ahmed,
E N Ragozin,
A Ya Faenov,
T A Pikuz,
T Kawachi,
A Sagisaka, [......],
K Kondo, T Kimura,
T Tajima,
H Daido,
P Rajeev,
P McKenna,
M Borghesi,
D Neely,
Y Kato,
S V Bulanov
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ABSTRACT: We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multiterawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving μJ/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.
Physical Review Letters 03/2012; 108(13):135004. · 7.37 Impact Factor
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Hiromitsu Kiriyama,
Michiaki Mori,
Y Nakai,
T Shimomura,
H Sasao,
M Tanoue,
S Kanazawa,
D Wakai,
F Sasao,
H Okada, [......],
M Suzuki,
S Kondo,
K Kondo,
A Sugiyama,
P R Bolton,
A Yokoyama,
H Daido,
S Kawanishi, T Kimura,
T Tajima
[show abstract]
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ABSTRACT: Optical parametric chirped-pulse amplification (OPCPA) operation with low gain by seeding with high-energy, clean pulses is shown to significantly improve the contrast to better than 10(-10) to 10(-11) in a high-intensity Ti:sapphire laser system that is based on chirped-pulse amplification. In addition to the high-contrast broadband, high-energy output from the final amplifier is achieved with a flat-topped spatial profile of filling factor near 77%. This is the result of pump beam spatial profile homogenization with diffractive optical elements. Final pulse energies exceed 30 J, indicating capability for reaching peak powers in excess of 500 TW.
Optics Letters 05/2010; 35(10):1497-9. · 3.40 Impact Factor
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M. Mori,
A. Yogo,
H. Kiriyama,
M. Nishiuchi,
K. Ogura,
S. Orimo,
Jinglong Ma,
A. Sagisaka,
S. Kanazawa,
S. Kondo, [......],
K. Nemoto,
Il Woo Choi,
Tae Jun Yu,
Do-Kyeong Ko,
Jongmin Lee,
H. Daido,
T. Esirkepov,
S.V. Bulanov,
P.R. Bolton, T. Kimura
[show abstract]
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ABSTRACT: A dependence of cutoff proton kinetic energy on laser prepulse duration has been observed. Amplified spontaneous emission pedestal duration is controlled by a fast electrooptic pulse slicer where the rise time is estimated to be 130 ps. We demonstrate a new correlated spectral technique for determining this rise time using a stretched frequency-chirped pulse.
IEEE Transactions on Plasma Science 09/2008; · 1.17 Impact Factor
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A. S. Pirozhkov,
M. Kando,
T. Zh. Esirkepov,
J. Ma,
Y. Fukuda,
L.‐M. Chen,
I. Daito,
K. Ogura,
T. Homma,
Y. Hayashi,
H. Kotaki,
A. Sagisaka,
M. Mori,
J. K. Koga,
T. Kawachi,
H. Daido,
S. V. Bulanov, T. Kimura,
Y. Kato,
T. Tajima
[show abstract]
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ABSTRACT: Upon reflection from a relativistic mirror, the electromagnetic pulse frequency is upshifted and the duration is shortened by the factor proportional to the relativistic gamma‐factor squared due to the double Doppler effect. We present the results of the proof‐of‐principle experiment for frequency upshifting of the laser pulse reflected from the relativistic “flying mirror”, which is a wake wave near the breaking threshold created by a strong driver pulse propagating in underdense plasma. Experimentally, the wake wave is created by a 2 TW, 76 fs Ti:S laser pulse from the JLITE‐X laser system in helium plasma with the electron density of ≈ 4–6×1019 cm−3. The reflected signal is observed with a grazing‐incidence spectrograph in 24 shots. The wavelength of the reflected radiation ranges from 7 to 14 nm, the corresponding frequency upshifting factors are ∼ 55–115, and the gamma‐factors are y = 4–6. The reflected signal contains at least 3×107 photons/sr. This effect can be used to generate coherent high‐frequency ultrashort pulses that inherit temporal shape and polarization from the original (low‐frequency) ones. Apart from this, the reflected radiation contains important information about the wake wave itself, e.g. location, size, phase velocity, etc.
AIP Conference Proceedings. 06/2008; 1024(1):37-51.
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M Nishiuchi,
H Daido,
A Yogo,
A Sagisaka,
K Ogura,
S Orimo,
M Mori,
J Ma,
A S Pirozhkov,
H Kiriyama, [......],
S Nakamura,
I W Choi,
T J Yu,
J H Sung,
H T Kim,
T M Jeong,
K -H Hong,
Y -C Noh,
D -K Ko,
J Lee
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ABSTRACT: We have performed simultaneous proton and X-ray imaging with an ultra-short and high-intensity Ti: Sap laser system. More than 1010 protons, whose maximum energy reaches 2.5 MeV, were delivered within a ~ps bunch. At the same time, keV X-ray is generated at almost the same place where protons are emitted. We have performed the simultaneous imaging of the copper mesh by using proton and x-ray beams, in practical use of the characteristics of the laser produced plasma that it can provide those beams simultaneously without any serious problems on synchronization.
Journal of Physics Conference Series 06/2008; 112(4):042036.
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A S Pirozhkov,
T Z Esirkepov,
M Kando,
Y Fukuda,
J Ma,
L-M Chen,
I Daito,
K Ogura,
T Homma,
Y Hayashi,
H Kotaki,
A Sagisaka,
M Mori,
J K Koga,
T Kawachi,
H Daido,
S V Bulanov, T Kimura,
Y Kato,
T Tajima
[show abstract]
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ABSTRACT: Electromagnetic wave frequency upshifting upon reflection from a relativistic mirror (the double Doppler effect) can be used for the generation of coherent high-frequency radiation. The reflected high-frequency pulse inherits the coherence, polarization, and temporal shape from the original laser pulse. A partly reflecting relativistic mirror (flying mirror) can be formed by a breaking wake wave created by a strong laser pulse propagating in underdense plasma [Bulanov S V et al. 2003 Phys. Rev. Lett. 91, 085001]. We present the results of the proof-of-principle experiment for frequency upshifting of the laser pulse reflected from the flying mirror. In the experiment, the breaking wake wave is created by a Ti:S laser pulse (2 TW, 76 fs) in helium plasma with the electron density of ~5×1019 cm-3. The incidence angle of the second laser pulse on the flying mirror is 45°. The reflected signal is observed in 24 shots, with the wavelength from 7 to 14 nm, which corresponds to the frequency upshifting factors from 55 to 114 and the relativistic gamma-factors from 4 to 6. The reflected signal contains at least 3×107 photons/sr. The new source promises the generation of coherent ultrashort XUV and x-ray pulses with tunable wavelength and duration, with the possibility of focusing to record intensities.
Journal of Physics Conference Series 06/2008; 112(4):042050.
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K Kawase,
M Kando,
T Hayakawa,
I Daito,
S Kondo,
T Homma,
T Kameshima,
H Kotaki,
L-M Chen,
Y Fukuda,
A Faenov,
T Shizuma,
M Fujiwara,
S V Bulanov, T Kimura,
T Tajima
[show abstract]
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ABSTRACT: Reported in this article is the generation of unique polarized x-rays in the sub-MeV region by means of the Thomson backscattering of the Nd:YAG laser photon with a wavelength of 1064 nm on the 150 MeV electron from the microtron accelerator. The maximum energy of the x-ray photons is estimated to be about 400 keV. The total energy of the backscattered x-ray pulse is measured with an imaging plate and a LYSO scintillator. The angular divergence of the x-rays is also measured by using the imaging plate. We confirm that the x-ray beam is polarized according to the laser polarization direction with the Compton scattering method. In addition, we demonstrate the imaging of the object shielded by lead with the generated x-rays.
Review of Scientific Instruments 06/2008; 79(5):053302. · 1.37 Impact Factor
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A Yogo,
H Daido,
S V Bulanov,
K Nemoto,
Y Oishi,
T Nayuki,
T Fujii,
K Ogura,
S Orimo,
A Sagisaka,
J-L Ma,
T Zh Esirkepov,
M Mori,
M Nishiuchi,
A S Pirozhkov,
S Nakamura,
A Noda,
H Nagatomo, T Kimura,
T Tajima
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ABSTRACT: Duration-controlled amplified spontaneous emission with an intensity of 10(13) W/cm(2) is used to convert a 7.5-microm -thick polyimide foil into a near-critical plasma, in which the p -polarized, 45-fs , 10(19) -Wcm (2) laser pulse generates 3.8-MeV protons, emitted at some angle between the target normal and the laser propagation direction of 45 degrees . Particle-in-cell simulations reveal that the efficient proton acceleration is due to the generation of a quasistatic magnetic field on the target rear side with magnetic pressure inducing and sustaining a charge separation electrostatic field.
Physical Review E 02/2008; 77(1 Pt 2):016401. · 2.26 Impact Factor
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M Kando,
Y Fukuda,
A S Pirozhkov,
J Ma,
I Daito,
L-M Chen,
T Zh Esirkepov,
K Ogura,
T Homma,
Y Hayashi,
H Kotaki,
A Sagisaka,
M Mori,
J K Koga,
H Daido,
S V Bulanov, T Kimura,
Y Kato,
T Tajima
[show abstract]
[hide abstract]
ABSTRACT: In a plasma wake wave generated by a high power laser, modulations of the electron density take the shape of paraboloidal dense shells, moving almost at the speed of light. A counterpropagating laser pulse is partially reflected from the shells, acting as relativistic flying mirrors, producing a time-compressed frequency-multiplied pulse due to the double Doppler effect. The counterpropagating laser pulse reflection from the plasma wake wave accompanied by its frequency multiplication (with a factor from 50 to 114) was detected in our experiment.
Physical Review Letters 10/2007; 99(13):135001. · 7.37 Impact Factor
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H. Daido,
A. Sagisaka,
K Ogura,
S Orimo,
M Nishiuchi,
M Mori,
J Ma,
A. Pirozhkov,
H Kiriyama,
S Kanazawa, [......],
S Nakamura,
I.W. Choi,
T.J. Yu,
J H Sung,
H T Kim,
T.M. Jeong,
K H Hong,
Y.-C. Noh,
D.-K. Ko,
J Lee
[show abstract]
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ABSTRACT: We are developing a proton accelerator using an intense lasers with a focused intensity of >10<sup>17</sup> W/cm<sup>2</sup>. To monitor proton energy spectra as well as plasma parameters at each laser shot, we are using real time detectors. The proton energy of ~MeV is stably obtained for applications.
Lasers and Electro-Optics - Pacific Rim, 2007. CLEO/Pacific Rim 2007. Conference on; 09/2007
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M. Kando,
Y Fukuda,
A S Pirozhkov,
J Ma,
I. Daito,
L M Chen,
T Zh Esirkepov,
K Ogura,
T Homma,
Y Hayashi,
H Kotaki,
A. Sagisaka,
M Mori,
J. K. Koga,
H. Daido,
S V Bulanov, T Kimura,
Y Kato,
T Tajima
[show abstract]
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ABSTRACT: Since the advent of chirped pulse amplification1 the peak power of lasers has grown dramatically and opened the new branch of high field science, delivering the focused irradiance, electric fields of which drive electrons into the relativistic regime. In a plasma wake wave generated by such a laser, modulations of the electron density naturally and robustly take the shape of paraboloidal dense shells, separated by evacuated regions, moving almost at the speed of light. When we inject another counter-propagating laser pulse, it is partially reflected from the shells, acting as relativistic flying (semi-transparent) mirrors, producing an extremely time-compressed frequency-multiplied pulse which may be focused tightly to the diffraction limit. This is as if the counterstreaming laser pulse bounces off a relativistically swung tennis racket, turning the ball of the laser photons into another ball of coherent X-ray photons but with a form extremely relativistically compressed to attosecond and zeptosecond levels. Here we report the first demonstration of the frequency multiplication detected from the reflection of a weak laser pulse in the region of the wake wave generated by the driver pulse in helium plasma. This leads to the possibility of very strong pulse compression and extreme coherent light intensification. This Relativistic Tennis with photon beams is demonstrated leading to the possibility toward reaching enormous electromagnetic field intensification and finally approaching the Schwinger field, toward which the vacuum nonlinearly warps and eventually breaks, producing electron-positron pairs.
06/2007;
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M. Mori,
M. Kando,
I. Daito,
H. Kotaki,
Y. Hayashi,
A. Yamazaki,
K. Ogura,
A. Sagisaka,
J. Koga,
K. Nakajima,
H. Daido,
S.V. Bulanov, T. Kimura
[show abstract]
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ABSTRACT: The regimes of quasi-monoenergetic electron beam generation were experimentally studied in the sub-relativistic intensity laser plasma interaction. The observed electron acceleration regime is unfolded with two-dimensional-particle-in-cell simulations of laser-wakefield generation in the self-modulation regime.
Physics Letters A. 05/2006;
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H Kiriyama,
M Michiaki,
Y Nakai,
T Shimomura,
H. Sasao,
M Tanaka,
Y Ochi,
M Tanoue,
H Okada,
S Kondo, [......],
S Bulanov,
PR Bolton,
H. Daido,
S Kawanishi,
JL Collier,
C Hernandez-Gomez,
CJ Hooker,
K Ertel, T Kimura,
T Tajima
[show abstract]
[hide abstract]
ABSTRACT: We have developed a femtosecond high-intensity laser system that combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric CPA (OPCPA) techniques and produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500TW. With a cleaned high-energy seeded OPCPA preamplifier as a front end in the system, for the compressed pulse without pumping the final amplifier, we found that the temporal contrast in this system exceeds 10e10 on the subnanosecond time scales, and is near 10e12 on the nanosecond time scale prior to the peak of the main femtosecond pulse. Using diffractive optical elements for beam homogenization of a 100 J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with a near-perfect top-hat-like intensity distribution.
