Skip to main content

Scientific Assessment of High-Power Free-Electron Laser Technology (2009) / Chapter Skim
Currently Skimming:

2 State of the Art
Pages 7-13

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 7...
... Unfortunately, at high power the molecular absorption component of the atmospheric extinction was determined to cause an unacceptably high level of thermal blooming to be useful for self-defense. (Thermal blooming results from a small amount of heating due to atmospheric absorption in the middle of the laser wavefront, causing beam spreading.)
Read the entire page →
From page 8...
... In the next column, σz is the electron pulse length divided by the speed of light, c, and ranges from 25 ns to short subpicosecond pulse timescales. The expected optical pulse length in an FEL oscillator can be three to five times shorter or longer than the electron pulse depending on the optical cavity Q, the FEL desynchronism, and the FEL gain.
Read the entire page →
From page 9...
... 0.03-0.06 1 250 300 600 1.5 0.3-1.5 RF,S DESY (FLASH) 0.0065 0.025 1,000 2,000 984 2.73 0.81 RF,S NOTE: λ, optical wavelength; σz, pulse length; E, beam energy; I, beam peak current; N, number of undulator periods; λo, undulator period; K, undulator parameter; RF, radio-frequency linac; EA, electrostatic accelerator; ERL, energy recovery linac; MA, microtron accelerator; SR, electron storage ring; A, FEL amplifier; O, FEL oscillator; Kl, FEL klystron; S, self-amplified spontaneous emission (SASE)
Read the entire page →
From page 10...
... In the case of the FEL amplifier, there is no optical resonator; a seed laser sends optical pulses synchronized to overlap the electron pulses as they enter the undulator. After the undulator, the electron beam continues at reduced average energy (E0 − ∆E)
Read the entire page →
From page 11...
... A principal obstacle to scale-up to megawatt power levels is the removal of waste heat from the solid-state gain medium. As the gain medium heats, optical quality is lost as the medium distorts, and eventually heating will kill the gain.
Read the entire page →
From page 12...
... In particular, the committee notes the emergence of the x-ray FEL and its connection with advances made in the emittance of nanocoulomb charge beams from RF electron guns, the development of superconducting RF guns, and the development of energy recovery linacs, advanced by the synchrotron radiation community and electron cooling technology. Crucial to the realization of turnkey, high-average-power FELs in the wavelength region of interest for Navy applications is the synergy between the advances in hardware and software simulations that have occurred during the past decade.
Read the entire page →
From page 13...
... Undulator magnets generate narrow spectral lines, which enhances the overall photon brilliance. Next-generation light sources involve an optical gain mechanism, with the goal of transverse and longitudinal optical coherence such as in an FEL.
Read the entire page →

Key Terms

  • electron pulses
  • synchrotron radiation
  • fel amplifier
  • energy recovery
  • optical pulse

  • fel oscillator
  • beam quality
  • pulse length
  • gain medium
  • light sources

  • electron pulse
  • electron lasers
  • optical power
  • optical pulses
  • fel klystron

  • optical resonator
  • beam energy
  • drive laser
  • megawatt power
  • wavelength regions

  • wavelength region
  • recovery linac
  • radiation users
  • power levels
  • storage ring

  • optical beam
  • fel gain
  • free electron
  • electron storage
  • optical mode


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.