This wave causes the electron to oscillate and to emit waves of equal wavelength. Rp photonics encyclopedia free electron lasers, fel. The light is emitted as the electron beam bunches into many very thin. The classical theory of fels is an extension of the theory of the ubitron developed by phillips 3, 4. Advances in inverse free electron laser accelerators and. Freeelectron lasers as pumps for highenergy solidstate lasers. The free electron laser utilizes the synchrotron effect in order to create a linear photon coherent beam similar to the one from lasers in it directionality and coherence.
The effects on ifel acceleration with respect to the variation of the laser electric field, the input. Xray freeelectron laser oscillator xfelo is expected to be a. It is predicted that this design with 95 ghz, te 3,1 will yield a peak output power of 264. In 1998 he joined the faculty of the university of hawaii where he is currently an associate professor of physics. Thus, the emitted wavelength in the electron reference frame is l. In order to get fully coherent radiation from the free electron laser fel amplifier starting from the shot noise, it is foreseen to implement a seeding option into the vuv fel being under.
Because the electrons do not transition between welldefined energy levels, some specialists question. On the theory of the free electron laser springerlink skip to main content. The free electron laser was invented by john madey in 1971 at stanford university. Va introduction to the physics of free electron laser. Free electron lasers produced by the resonant interaction of a relativistic electron beam with a photon beam in an undulator tunable, powerful, coherent radiation sources 1977 first operation of a freeelectron laser at stanford university today 22 freeelectron lasers operating worldwide 19 fels proposed or in construction. Free electron lasers as pumps for highenergy solidstate lasers g. The electron, therefore, sees the undulator as an electromagnetic wave fig. At the first glance, this phasemerging phenomenon is very similar with the electron beam energy spread cooling.
In order to combine the advantages of these two schemes, fel. The free electron laser fel will be an outstanding tool for research and industrial application. Navy reports breakthrough with game changing laser cbs. Other articles where free electron laser is discussed. Soon after the discovery of the principle of a freeelectron laser madey. Pdf analytical theory of shortpulse freeelectron laser. Fels were developed from the work on free electron beams. First lasing and operation of an angstromwavelength free. A freeelectron laser consists of an electron beam propagating through a periodic magnetic field.
Us particle acceus particle accelerator school 2009lerator school 2009 university of new mexico albuquerque nm how an fel works contd the wiggler induces transverse sinusoidal velocity in electron beam energy exchange occurs between the transverse electron current and transverse electric field of a copropagating light beam. Motz showed in 1951 that an electron beam propagating through an undulator magnet could be used to amplify. In solidstate physics, the free electron model is a simple model for the behaviour of charge carriers in a metallic solid. In free electron lasers stimulated emission comes from electrons passing through a magnetic field that periodically varies in direction and intensity, causing the electrons to accelerate and release light energy. The model describes the 3d spatial and temporal evolution of the electron and radiation beams, including di raction, propagation, laser wiggler, emittance and quantum recoil e ects. The optical mode is guided by the electron beam, having a mode width that depends upon the gain length.
High brightness fully coherent xray amplifier seeded by a free. The optical resonator with macroscopic dimensions that could store significant optical power at short wavelengths was crucial to the invention of the laser. While related works 3442, investigate fel quantum theory mainly with. Free electron laser fel theory is extended to explain several effects associated with high. Laser physics started with quantum mechanics, at the beginning of the. Because of the wavelength scaling, the freeelectron laser is capable of producing very high. Electron vortex orbits and merger university of california. Jefferson labs freeelectron laser is the worlds highestpower tunable infrared laser and was developed using the labs expertise in superconducting radiofrequency srf accelerators. In this paper, we revie w the basic theory of the startup, the. A special laser heater27,28 is located in the injector at 5 mev heater in fig. Pdf a freeelectron laser consists of an electron beam propagating through a periodic magnetic field. Jan 24, 2011 navy reports breakthrough with game changing laser.
For the case of a wide electron beam, the dispersion relation converges with that of the 2d theory. Path to understanding nobel symposium on free electron laser research june 14 18, 2015 sigtuna, sweden john m. The wiggler and the radiation combine to produce a beat wave, which is essentially an interference. The free electron laser fel is a natural alternative as a radiation source national research council, 1982. History of free electron laser fel the fel is the result of many years of theoretical and experimental work on the generation of radiation from relativistic electron beams.
Freeelectron laser wikipedia, the free encyclopedia. Electric force acts on electrons along their direction of motion and thus changes the electrons kinetic energy. However, seen in the laboratory reference frame fig. Novel electron accelerator techniques can be used to create free electron lasers in a wide wave length interval extending to the xray region, i. Navy reports breakthrough with game changing laser. Physics of the freeelectron laser lasers, photonics, and. Physics of the free electron laser the free electron laser can produce intense, coherent light as the result of the interaction between an electron beam and an electric field of light. A freeelectron laser fel is a kind of laser whose lasing medium consists of veryhighspeed. Classical theory of freeelectron lasers book iopscience. A free electron laser fel operating in the quantum regime can provide a compact and monochromatic xray source. Pdf an introduction to the theory of free electron lasers. Nonlinear compton processes and pair creation from electron beam crossed with laser beam.
Freeelectron laser an overview sciencedirect topics. The laser is a device which is today used in a wide list of fields. A free electron laser consists of an electron beam propagating through a periodic magnetic field. The free electron laser utilizes technology developed by hans motz and his coworkers, who built an undulator at stanford in 1953, using the wiggler magnetic configuration which is one component of a free electron laser. Building an optical freeelectron laser in the traveling. Laser is an acronim for light amplification by stimulated emission of radiation. Today such lasers are used for research in materials science, chemical technology, biophysical. An analysis of the linearized system allows the definition and. A simplified description of xray freeelectron lasers. Smith 1,2 1 naval postgraduate school, monterey, ca 93943 2 stanford university, stanford, ca 94305 abstract the naval postgraduate school nps is in the process of designing and constructing a free electron laser fel. On the theory of the free electron laser springerlink.
A free electron laser fel, is a type of laser that uses veryhighspeed electrons that move freely through a magnetic structure, 1 hence the term free electron as the lasing medium. Highgain freeelectron lasers fels are being developed as extremely bright sources for a next generation xray facility. A simple model for the nonlinear evolution of a shortpulse free electron laser oscillator in the small gain regime is derived. Introduction to free electron lasers and fourthgeneration. A free electron laser, or fel, is a laser that produces a very bright beam of light. Phasemerging enhanced harmonic generation free electron laser. Free electron lasers 2002 1st edition proceedings of the 24th international free electron laser conference and the 9th fel users workshop, argonne, illinois, u. Choosing the required parameters laser resonators for fels fel output characteristics fel vs conventional laser current trends.
It can be solved numerically and reduces to the 3d maxwellvlasov model in the classical limit. The influences of the velocity pitch, frequency, and input power of the electron beam on efficiency, output power, and saturated gain are simulated and discussed in detail. Freeelectron laser simple english wikipedia, the free. Free electron lasers an overview sciencedirect topics.
Navy reports breakthrough with game changing laser cbs news. Emphasis is put on the realization of optical freeelectron lasers. Free electron lasers are laser devices where light amplification occurs by interaction with fast electrons in an undulator. Recent advances regarding xray freeelectron lasers in the awavelength. It was developed in 1927, principally by arnold sommerfeld, who combined the classical drude model with quantum mechanical fermidirac statistics and hence it is also known as the drudesommerfeld model. Pdf operation of a freeelectron laser from the extreme. For shorter wavelength, some novel schemes such as echoenabled harmonic generation eehg and phasemerging enhanced harmonic. In a storage ring free electron laser fel they can compete with the induced beam heating and thus be treated as a further concomitant perturbing source of the beam dynamics. What exactly is the difference between a sychrotron light.
The fel also provides ultraviolet laser light, including vacuum ultraviolet light, and is also a source of terahertz light. His current research interests include the theory and design of novel optical resonators for highresolution free electron laser spectroscopy, xray generation and highfield physics. Properties and prospects1 gunnar ingelman and kai siegbahn uppsala university abstract. Laser rate equations university of california, davis. These keywords were added by machine and not by the authors. The very first electromagnetic radiation amplifier was built with ammonia in the range of microwaves and was called maser, for microwave amplification by stimulated emission of radiation. Pdf we report results on the performance of a freeelectron laser. In the following we sketch the fully classical theory following atomicmolecular laser theory based on the coupled maxwellbloch theory as it was first published in 1976. Due to the coherent emission, very large intensities. A freeelectron laser fel, is a type of laser that uses veryhighspeed electrons that move freely through a magnetic structure, 1 hence the term free electron.
Slippage boosted spectral cleaning in a seeded freeelectron laser. Advances in inverse free electron laser accelerators and implications for high efficiency fels p. Each electron emits a wave train with n u cycles 1n u n u. Experimental and numerical studies of the inverse free electron laser using a gwlevel 10. The question of a classical theory of fel operation was very much in the air in the early days 19731976. This process is experimental and the keywords may be updated as the learning algorithm improves. If you want to obtain moving images of highspeed molecular processes at an atomic scale, one of the best facilities in the world is the xray free electron laser xfel at stanford university. This tool allows a user to alter the parameters in the laser rate equations, while plotting three unique graphs. Freeelectron lasers with higher average power and shorter wavelengths are.
84 1566 817 526 1607 1028 709 1577 678 1165 850 1551 165 361 643 131 945 468 252 895 378 1238 703 1258 336 1282 392 538 1244 288 83 281 1126 1431 319 770 615 1210 636 1004 782 308 1010 561 858 966 389