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Papers by Shuanglei Li
Frontiers in Optics 2011/Laser Science XXVII, 2011
ABSTRACT This talk provides the summary of experimental research at Princeton on Raman Backscatte... more ABSTRACT This talk provides the summary of experimental research at Princeton on Raman Backscattering (RBS) amplification and compression in plasma [1]. The main subject of the talk is about obtaining high efficiency of such system [2,3].
Physics of Plasmas, 2008
The enhancement of stimulated Raman backscattering (SRBS) amplification was demonstrated by intro... more The enhancement of stimulated Raman backscattering (SRBS) amplification was demonstrated by introducing a plasma density gradient along the pump and the seed interaction path and by a novel double-pass design. The energy transfer efficiency was significantly improved to a level of 6.4%. The seed pulse was amplified by a factor of more than 20 000 from the input in a 2mm long plasma, which also exceeded the intensity of the pump pulse by 2 orders of magnitude. This was accompanied by very effective pulse compression, from 500fsto90fs in the first pass measurements and in the second pass down to approximately 50fs, as it is indicated by the energy-pulse duration relation. Further improvements to the energy transfer efficiency and the SRBS performance by extending the region of resonance is also discussed where a uniform ∼4mm long plasma channel for SRBS was generated by using two subsequent laser pulses in an ethane gas jet.
Physics of Plasmas, 2012
ABSTRACT In a Raman plasma amplifier, the aim is to create plasma conditions in which Raman backs... more ABSTRACT In a Raman plasma amplifier, the aim is to create plasma conditions in which Raman backscattering is the fastest growing instability, outrunning all competing effects so that it is possible to amplify and compress a laser beam to unprecedented unfocused intensities by utilizing that instability. However, achieving high efficiencies via this scheme has proven very difficult experimentally. Recent data show the simultaneous occurrence of stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), and stimulated electron-acoustic scattering (SEAS). The appearance of SEAS is indicative of strong particle trapping, the existence of which is hard to justify without highlighting the interplay between SRS and SBS.
A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short... more A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short laser pulses should, in principle, convert almost all of the pump energy to the seed pulse. ootnotetextV. M. Malkin, G. Shvets, and N. J. Fisch, Phys. Rev. Lett. 82, 4448 (1999). However, while the theoretically possible efficiency of this scheme has not yet been achieved, accompanied by strong pulse compression larger efficiencies than ever before obtained experimentally are now being reported. ootnotetextJ. Ren et al, invited talk, this Bulletin These higher experimental efficiencies may be due to favorable compensation between laser parameters, including the chirp of the laser, and the density variations of the mediating plasma. This compensation may extend the region of resonance. The physical mechanisms, which might produce these effects, will be considered in light of the experimental data. This work is supported by DOE grant DE-FG52-07NA28122.
Frontiers in Optics 2011/Laser Science XXVII, 2011
ABSTRACT This talk provides the summary of experimental research at Princeton on Raman Backscatte... more ABSTRACT This talk provides the summary of experimental research at Princeton on Raman Backscattering (RBS) amplification and compression in plasma [1]. The main subject of the talk is about obtaining high efficiency of such system [2,3].
Physics of Plasmas, 2008
The enhancement of stimulated Raman backscattering (SRBS) amplification was demonstrated by intro... more The enhancement of stimulated Raman backscattering (SRBS) amplification was demonstrated by introducing a plasma density gradient along the pump and the seed interaction path and by a novel double-pass design. The energy transfer efficiency was significantly improved to a level of 6.4%. The seed pulse was amplified by a factor of more than 20 000 from the input in a 2mm long plasma, which also exceeded the intensity of the pump pulse by 2 orders of magnitude. This was accompanied by very effective pulse compression, from 500fsto90fs in the first pass measurements and in the second pass down to approximately 50fs, as it is indicated by the energy-pulse duration relation. Further improvements to the energy transfer efficiency and the SRBS performance by extending the region of resonance is also discussed where a uniform ∼4mm long plasma channel for SRBS was generated by using two subsequent laser pulses in an ethane gas jet.
Physics of Plasmas, 2012
ABSTRACT In a Raman plasma amplifier, the aim is to create plasma conditions in which Raman backs... more ABSTRACT In a Raman plasma amplifier, the aim is to create plasma conditions in which Raman backscattering is the fastest growing instability, outrunning all competing effects so that it is possible to amplify and compress a laser beam to unprecedented unfocused intensities by utilizing that instability. However, achieving high efficiencies via this scheme has proven very difficult experimentally. Recent data show the simultaneous occurrence of stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), and stimulated electron-acoustic scattering (SEAS). The appearance of SEAS is indicative of strong particle trapping, the existence of which is hard to justify without highlighting the interplay between SRS and SBS.
A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short... more A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short laser pulses should, in principle, convert almost all of the pump energy to the seed pulse. ootnotetextV. M. Malkin, G. Shvets, and N. J. Fisch, Phys. Rev. Lett. 82, 4448 (1999). However, while the theoretically possible efficiency of this scheme has not yet been achieved, accompanied by strong pulse compression larger efficiencies than ever before obtained experimentally are now being reported. ootnotetextJ. Ren et al, invited talk, this Bulletin These higher experimental efficiencies may be due to favorable compensation between laser parameters, including the chirp of the laser, and the density variations of the mediating plasma. This compensation may extend the region of resonance. The physical mechanisms, which might produce these effects, will be considered in light of the experimental data. This work is supported by DOE grant DE-FG52-07NA28122.