Abstract
The recently proposed backward Raman laser amplification scheme utilizes the stimulated Raman backscattering in plasma of a long pumping laser pulse to amplify a short, and frequency downshifted seed pulse. The output intensity for this scheme is limited by the development of forward Raman scattering (FRS) or modulational instabilities of the highly amplified seed. Theoretically, focused output intensities as high as 10 25 W/cm 2, and pulse lengths of less than 100 fs, could be accessible by this technique for 1 μm lasers - an improvement of 10 4-10 5 in focused intensity over current techniques. Simulations with the particle-in-cell (PIC) code Zohar are presented, which investigate the effects of FRS and modulational instabilities, and of Langmuir wave breaking on the output intensity for Raman amplification. Using the intense seed pulse to photoionize the plasma simultaneous with its amplification (and hence avoid plasmas-based instabilities of the pump) is also investigated by PIC simulations. It is shown that both approaches can access focused intensities in the 10 25 W/cm 2 range.
Original language | English (US) |
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Pages (from-to) | 101-106 |
Number of pages | 6 |
Journal | Laser and Particle Beams |
Volume | 23 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2005 |
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering
Keywords
- Langmuir wave-breaking
- Laser ionization
- Laser-plasma interaction
- Raman laser amplification
- Raman scattering