Applied Physics

Light-Based Particle Accelerators

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Science  12 Oct 2001:
Vol. 294, Issue 5541, pp. 267
DOI: 10.1126/science.294.5541.267a

Most people own their own particle accelerators. In the back of a television set, electrons are emitted from a cathode and accelerated and maneuvered by electric and magnetic fields toward the phosphor screen. The same principle of electron acceleration is used in large particle accelerators, only on a much grander scale. Reducing the size of accelerators without compromising the need for very high particle energies is a goal for the next generation of accelerators. Because light is an electromagnetic field, schemes are being devised that use light to accelerate electrons.

Zawadzka et al. demonstrate that shining femtosecond pulses of intense laser light on a thin film of silver or gold produces an evanescent light field that extends from the surface and can accelerate photo-emitted electrons up to energies approaching 400 electron volts. Although this energy is quite modest compared with those achieved in traditional particle accelerators, calculations show that higher, perhaps even relativistic, energies may be possible by using longer wavelength light pulses or by modulating the film surface to enhance the interaction between the light and the electrons.—ISO

Appl. Phys. Lett.79, 2130 (2001).

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