Waveform control in generations of intense water window attosecond pulses via multi-color combined field

摘要: The waveform control in the improvements of high-order harmonic generation (HHG) spectra and attosecond pulse signals driven by two-color three-color combined fields has been theoretically investigated. (a) results show that properly controlling omega-2 omega laser beam (including modulations chirps, carrier envelope phases delay time), either cutoff can be extended, showing a water window spectral continuum, or selective enhancement single-order two-order harmonics found. Further, with introduction third field, efficiency continuum enhanced two orders magnitude compared from field. Moreover, HHG is not very sensitive to frequency field (i.e., chosen 3 omega, 4 6 omega). Thus, some pulses durations 60 as obtained. (b) Furthermore, further extended when using half-cycle introducing inhomogeneous effect improved initial state prepared superposition ground excited He atom. Consequently, much broader an intensity another Finally, through Fourier transformation intense produced.