Wigner time-frequency distribution of high-order harmonics
نویسندگان
چکیده
We investigate the time-frequency characteristics of high-order harmonics generated in atomic gases by intense femtosecond laser pulses, using the Wigner distribution function. The dynamically induced chirp of high harmonics is calculated both quantum mechanically and semiclassically, and a good agreement between them is reached as long as the tunneling effect is properly taken into account. Using the time-frequency analysis, we demonstrate that the large harmonic blueshift observed experimentally is due mainly to the single-atom effect.
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تاریخ انتشار 2001