Description

The interactions between intense laser pulses and a solid target generate energetic and intense radiations such as electrons, ions, and x-rays. Since these radiations are driven at a time and space scale resembling the pulse width and focusing diameter of the laser, they have the characteristic of short pulse and high brightness. Researches have been achieved to apply these radiations as probe pulses, which have a short pulse and high brightness. The laser-driven charged particles, for example, are possible to measure electromagnetic fields varying with ultra-high-speed. In proton radiography, it is observed the spatial distribution of electromagnetic fields that change within a few picoseconds from moment to moment [1]. On the other hand, since the laser-accelerated electrons have a pulse width of less than picoseconds, they can observe an electric field varying at a higher speed [2]. Also, since electrons are much lighter than protons, they are sensitive to electromagnetic fields with small amplitudes that protons cannot measure. Therefore, this electron pulse has the potential for measuring the ultrafast fields such as laser-induced plasmas with high spatial and temporal resolutions.

Here, we report measurements for fs-laser-induced plasma waves with laser-accelerated electron pulses. By using electrons pulses as a backlight for electric fields, spatial distributions of electric fields have been measured with a time resolution of hundreds of femtosecond. Electron pulses are generated by irradiating an Al foil with a Ti:Sapphire laser (pulse width: 40fs, pulse energy: 100mJ). Electron pulses with a pulse width of 89 fs, the energy of 370 keV, a charge amount of 20 fC, and a beam size of 3.5 mm × 1.5 mm have been used for measuring femtosecond laser-induced plasma waves. With these electron pulses, the temporal and spatial distribution of the plasma waves generated by the interaction between the femtosecond laser pulse at a fluence of 1kJ/cm2 and a tungsten wire was measured.

[1] L. Romagnani et al Phys. Rev. Lett. 95, 195001 (2005).

[2] S. Tokita et al. Sci. Rep. 5, 8268 (2015); S. Inoue et at. Appl. Phys. Lett. 99, 31501 (2011).

Contributing Authors

  • Shunmsuke Inoue
    Kyoto University
  • Masaki Hashida
    Kyoto University
  • Shuji Sakabe
    Kyoto University
Shunmsuke Inoue
Kyoto University
Track: Laser Nanomanufacturing
Session: Basics Physics of Laser Nanoprocessing
Day of Week: Monday
Date/Time:
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Keywords

  • Femtosecond Laser Ablation
  • Intense Laser
  • Ultrafast Electron Pulse