Sergei V. Bulanov

Pulse Compression of Nd:YAG Laser with Stimulated Brillouin Scattering for Compton Backscattered X‐ray Source

Compton backscattered x‐ray source is developed in the energy region of a few hundred keV at Kansai Photon Science Institute of Japan Atomic Energy Agency (KPSI‐JAEA). A remarkable feature of the Compton backscattered x‐ray source is that the generated x‐ray beam is a well‐collimated and has a definite polarization property. The Compton backscattered x‐ray source at KPSI‐JAEA consists of the 150‐MeV electron beam with the pulse duration of 24 ps accelerated by Microtron accelerator and a Nd:YAG laser with the pulse duration of 23 ns. At the first trial of the X‐ray generation, the x‐ray flux is not enough for actual use. As an actual x‐ray source, it is important to increase the generated x‐ray flux as much as possible. Thus, in order to increase the x‐ray flux, we develop the pulse compression system for the Nd:YAG laser through the stimulated Brillouin scattering (SBS). The SBS pulse compression is characterized by its high conversion efficiency and by its simplicity of construction. On this article, we describe the present status of the SBS pulse compression for the Compton backscattered x‐ray source at KPSI‐JAEA.

Experimental Characterization of Splash Plasma Channels for Guided Laser-Wake Field Acceleration

Yoshio Mizuta, Tomonao Hosokai, Shinichi Masuda, Alexei Zhidkov, Nobuhiko Nakanii, Zhan Jin, Hiroki Nakahara, Tomohiro Kohara, Kenta Iwasa, Masaki Kando, Sergei Bulanov, and Ryosuke Kodama 1 Graduate School of Engineering, Osaka University,2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan 2 Photon Pioneers Center, Osaka University, 2-8 Yamada-oka, Suita, Osaka, 565-0871, Japan 3 Japan Science and Technology Agency (JST), CREST 4 Kansai Photon Science Institute, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kidugawa, Kyoto 619-0215, Japan 5 Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka, 565-0871, Japan

Current Status and Future Prospects of “J-KAREN” — High Contrast, High Intensity Laser for Studying Relativistic Laser-Matter Interactions

Remarkable progress in recent years with Ti:sapphire chirped-pulse amplification (CPA) technique provides great opportunities for experimental study of laser matter interactions in the relativistic regime focusing petawatt-class laser pulses to intensities up to 10 to 10 W/cm. For most plasma physics research, the use of temporal contrast enhancing technique is required to suppress the unwanted intense prepulses that can generate significant preplasma at the target.

Recent progress in particle acceleration from the interaction between thin-foil targets and J-KAREN laser pulses

From the interaction between the high-contrast (∼more than 1010) 130 TW Ti:sapphire laser pulse and Stainless Steel-2.5 um-thick tape target, proton beam with energies up to 23 MeV with the conversion efficiency of ∼1% is obtained. After plasma mirror installation for contrast improvement, from the interaction between the 30 TW laser pulse and thin-foil target installed on the target holder with the hole whose shape is associated with the design of the well-known Wehnelt electrode of electron-gun, a 7 MeV intense proton beam is controlled dynamically and energy selected by the self-induced quasi-static electric field on the target holder. From the highly divergent beam having continuous spectrum, which are the typical features of the laser-driven proton beams from the interactions between the short-pulse laser and solid target, the spatial distribution of 7 MeV proton bunch is well manipulated to be focused to an small spots with an angular distribution of ∼10 mrad. The number of protons included in the b...

High-Intense, High-Contrast J-KAREN Laser at Advanced Photon Research Center

We demonstrate a compact high-intense, high contrast OPCPA/Ti:sapphire hybrid laser. The 80 TW peak power at 10 Hz repetition rate with ~9 orders temporal contrast in a few picoseconds region was obtained.