What is a free-electron laser?
Q: What is a free-electron laser?
A: A free-electron laser, or FEL, is a laser that produces a very bright beam of light. It shares the same optical properties as conventional lasers such as emitting a beam consisting of coherent electromagnetic radiation which can reach high power. Unlike gas, liquid, or solid-state lasers such as diode lasers, in which electrons are excited while bound to atoms, FELs use a relativistic electron beam as the lasing medium which moves freely through a magnetic structure.
Q: What range of frequencies does the free-electron laser cover?
A: The free-electron laser has the widest frequency range of any laser type and can be widely tunable. It currently ranges in wavelength from microwaves, through terahertz radiation and infrared, to the visible spectrum, to ultraviolet, to X-rays.
Q: Who invented the free-electron laser?
A: Free—electron lasers were invented by John Madey in 1976 at Stanford University.
Q: What was used to amplify signals for early experiments with FELs?
A: For early experiments with FELs John Madey used a 24 MeV electron beam and 5 m long wiggler to amplify signals.
Q: Who developed an earlier version of what would become an FEL?
A: Hans Motz and his coworkers developed an earlier version of what would become an FEL at Stanford in 1953 using the wiggler magnetic configuration which is at the heart of a free-electron laser.
Q: How much electricity do FELs use when they operate?
A: Free-electron lasers use a lot of electricity when they operate.
Q: How can scientists reduce energy needed for operation?
A: To reduce energy needed for operation scientist use an energy recovery linear accelerator to recycle the high-energy electron beam that activates the laser.
