Optimal control of filamentation in air

The authors demonstrate optimal control of the propagation of ultrashort, ultraintense (multiterawatt) laser pulses in air over distances up to 36 m in a closed-loop scheme. They optimized three spectral ranges within the white-light continuum as well as the ionization efficiency. Optimization results in signal enhancements by typical factors of 2 and 1.4 for the target parameters. The optimization results in shorter pulses by reducing their chirp in the case of white-light continuum generation, while they correct the pulse from its defects and set the filamentation onset near the detector as far as air ionization is concerned. (c) 2006 American Institute of Physics.