When an ultra-intense laser pulse impacts the tip of a wire whose other end is grounded, a strong return current can be driven along the wire because some energetic electrons generated in ultra-intense laser matter interaction can escape from the target and an electric field builds up. The wire then behaves like a current-carrying antenna that can emit electromagnetic radiations. If the duration of the driving pulse is several tens of femtoseconds, the radiation spectrum reaches a maximum at terahertz region, and the radiation power per solid angle could be as high as 10(9) W/rad. (C) 2007 American Institute of Physics.
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