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Particle Acceleration by Stimulated Emission of Radiation (PASER for Short), a sort of particle analog of the laser process, has been demonstrated, for the first time, by a team of physicists from the Technion-Israel Institute of Technology using the accelerator facilities at the Brookhaven National Lab.
 Four methods of transferring energy. (a) The Franck-Hertz experiment of 1914, which demonstrated that electrons passing through a vapor of mercury atoms could excite the atoms to higher energies. (b) The Latysheff-Leipunsky experiment of 1930 showing the inverse process: excited atoms could transfer some of their energy to passing electrons. (c) The laser process by which an excited atom can be stimulated to emit some of its energy as a photon in concert with a similar photon already moving through the resonant cavity. (d) The paser process in which excited atoms transfer energy not into creating photons but into accelerating electrons. Picture: aip.org
The electrons stimulate the atoms into giving up their surplus energy through collisions. The electrons' energy is amplified in a coherent way; that is, the electrons are directly accelerated by a direct and coordinated quantum transfer of energy. Although millions of collisions are involved for each electron, no heat is generated. The transferred energy goes into an enhanced electron motion. One could say that here was a laser which produced no laser light, only a laser-like transfer of energy resulting in electron acceleration.
 Experimental PASER setup. Electrons from an accelerator are modulated into short bursts by a co-moving CO2 laser and by the use of a
Being able to accelerate electrons with energy stored in individual atoms/molecules, a concept now demonstrated with the PASER, provides new opportunities since the accelerated electrons may prove to be significantly "cooler" (they are more collimated in velocity) than in some other prospective acceleration schemes, enabling in turn the secondary generation of high-quality X-rays, which are an essential tool in nano-science.
Related Links:
Banna, Berezovsky, Schachter, Physical Review Letters, upcoming article
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