Number 154 (Story #2), December 3, 1993 by Phillip F. Schewe and Ben Stein TABLE-TOP TERAWATT LASERS provide 10**12 watts of light energy in nanosecond or picosecond bursts. Until recently producing this sort of power required a room-sized labyrinthine system which splits the beam into several branches which are amplified in parallel (so as not to damage the laser rods) and then recombined at a target. A newer approach stretches the beam pulse with diffraction gratings, amplifies it, and then compresses it again in a process called "chirping." By working in the time domain rather than in space (farming out the beam to bulky ancillary laser amplifiers) this approach greatly lowers the size and expense of high-power laser systems. Alternatively, the chirped pulse amplification (CPA) technique can be coupled to existing lasers. For example, CPA helped boost the power of the VULCAN laser at Britain's Rutherford Appleton Lab to 10 Terawatts. Similar systems are used at Livermore, Rochester, and Saclay. The high electric fields in such light beams (higher than the fields that hold the hydrogen atom together, 5 x 10**11 V/m) can be sent through nonlinear crystals to produce higher harmonic waves, including x rays. It may also be possible to use such high fields to create waves (Langmuir waves) in a column of plasma which in turn can accelerate electron beams to higher energies than with present technology. (New Scientist, 20 Nov. 1993.)