Ivanov, IgorKheifets, Anatoli2015-12-101050-2947http://hdl.handle.net/1885/51577Increase in the cutoff value in the high-order harmonics generation process is demonstrated for a special case of the driving field composed of several harmonics of a given frequency. It is shown that a moderate, of the order of 20%, increase in the cutoff value can be achieved. This result possibly constitutes an upper limit for the increase in the cutoff value, attainable for a class of the waveforms considered in the paper.Keywords: Cut-off value; Driving field; High order harmonic generation; High order harmonics; Upper limits; Wave forms; Harmonic analysis; Cutoff frequency200910.1103/PhysRevA.80.0238092016-02-24