Using an extended Lewenstein model under single-active electron (SAE) and linear combination of atomic orbital approximations, we perform a theoretical investigation of the high harmonic generation (HHG) spectrum of diatomic molecular systems in intense short-pulse laser fields. The wavelet transform and Wigner distribution, two complementary time-frequency methods, are extended for the explora...

A theoretical model is developed describing high-order harmonic generation (HHG) from a gas of multiply-charged ions driven by a laser field of relativistic intensity. Macroscopic propagation of harmonics is investigated in a relativistic HHG setup where the relativistic drift is suppressed by means of x-ray field assistance of the driving laser field. The possibility of phase-matched emission ...

Dehydroepiandrosterone (DHEA) has a fat-reducing effect, while little information is available on whether DHEA regulates glucose metabolism, which would in turn affect fat deposition. To investigate the effects of DHEA on glucose metabolism, rats were administered a high-fat diet containing either 0 (HCG), 25 (HLG), 50 (HMG), or 100 (HHG) mg·kg-1 DHEA per day via gavage for 8 weeks. Results sho...

High harmonic generation (HHG) is a fascinating strong-field physics phenomenon that occurs when a laser pulse with a moderate intensity interacts with atoms and partially ionizes the atoms. A series of harmonics are generated at similar efficiencies and extend to a few tenth, even thousandth, order harmonics at the extreme ultraviolet (EUV) and soft X-ray range. Such an unprecedented broadband...

High order harmonic generation (HHG) from laser solid-density plasma interactions is considered as a promising way to generate bright and ultrashort burst of x-rays. One of the key issues for HHG is the low conversion efficiency due to a power law fall off in harmonic intensity. Here, we explore a possible mechanism for HHG enhancement by reflecting an intense laser pulse multiple times between...

Using a time-dependent density-functional-theory (TDDFT) method, we calculated the high-harmonic generation (HHG) spectra of N2 in 800and 1300-nm intense lasers. The calculations reproduce the experimentally observed minimum near 40 eV and the shift of the minimum due to interference of different molecular orbitals. They also support the proposed shape resonance near 30 eV. The TDDFT method all...

It is believed so far that the high harmonic generation (HHG) signal of adiabatically aligned molecules does not show any revival structure. This paper demonstrates the existence of revival structure of HHG signals of molecular ensemble aligned by using adiabatic as well as switched-off schema. The results are presented in the externally available control parameters – the delay-time, d t , betw...

We investigate high-order harmonic generation HHG in a thin macroscopic medium by solving Maxwell’s equation using microscopic single-atom induced dipole moment calculated from the recently developed quantitative rescattering QRS theory. We show that macroscopic HHG yields calculated from QRS compared well with those obtained from solving the single-atom time-dependent Schrödinger equation but ...

We describe the isolation and initial characterization of seven independent lambda Charon 4A recombinant phages which contain human histone genomic sequences (designated lambda HHG). Restriction maps of these clones and localization of the genes coding for histones H2A, H2B, H3, and H4 are presented. The presence of histone encoding regions in the lambda HHG clones was demonstrated by several i...

High-order harmonic generation (HHG) is a nonlinear nonperturbative process in ultrashort intense laser-matter interaction. It is the main source of coherent attosecond (1 as = 10 s) laser pulses to investigate ultrafast electron dynamics. HHG has become an important table-top source covering a spectral range from infrared to extreme ultraviolet (XUV). One way to extend the cutoff energy of HHG...