Streaking camera in the high intensity regime.

The laser-induced decay of an atomic system in an intense infrared and perturbative extreme ultraviolet (XUV) pulse is considered within Keldysh and streaking ionization channels. The streak camera method is discussed for two cases corresponding to different ranges of photoelectron momentum: i) the streaking channel significantly dominates the Keldysh channel and ii) the Keldysh channel of ionization is dominant, while two channels may interfere. The retrieval of XUV pulse parameters for these two cases is discussed and supported by numerical calculations.

Channel separation of secondary generated radiation induced by orthogonal XUV and IR pulses.

The secondary generated radiation induced by orthogonal linearly polarized extreme ultraviolet (XUV) and infrared (IR) pulses is analyzed for the spectral region of the second XUV harmonic. The polarization-filtering-based method is utilized to separate two spectrally overlapping and competing channels, which are the XUV second harmonic generation (SHG) by IR-dressed atom and XUV-assisted recombination channel of high-order harmonic generation in the IR field [Phys. Rev.

Using the generation of Brunel harmonics by elliptically polarized laser pulses for high-resolution detecting lower-frequency radiation.

We propose to use the generation of even Brunel harmonics (BHs) by optical laser pulses for high-resolution gas-biased coherent detection of lower-frequency radiation in terahertz and mid-infrared ranges. BHs arise due to the acceleration of electrons liberated in the tunneling ionization process, and BHs pulses are much shorter than the laser ones. The latter makes it possible to significantly increase the temporal resolution of sampling detection compared to the use of cubic response of bound electrons generating the second harmonic of the gating pulse.

Contribution of the collective electron dynamics to the polarization response of an atom subjected to intense IR and weak XUV pulses.

We analyze the polarization response of a single Ne atom in an intense infrared (IR) laser field and weak extreme ultraviolet (XUV) isolated attosecond pulse (IAP). The analysis is based on the numerical solution of the time-dependent Kohn-Sham equations and the recently developed perturbation theory in the XUV field for an atom subjected to an intense IR field. In our numerical results, we observe a significant increase in the magnitude of the atomic polarization response at the frequencies near the carrier frequency of the IAP and associate it with XUV-induced collective dynamics contributing to the polarizability of Ne.

Waveform retrieving of an isolated attosecond pulse using high-order harmonics generation of the superimposed infrared field.

An all-optical method is suggested for the metrology of an isolated, pulse-to-pulse stabilized attosecond pulse. It is shown analytically that high-order harmonic generation (HHG) yield for an intense IR pulse and time-delayed attosecond pulse keeps encoded waveform of the attopulse, which can be decoded by the time delay measurements of the HHG yield. The retrieval method is demonstrated by modeling HHG from Ne atom within time-dependent Kohn-Sham equations.