Supercontinuum generated by ultrashort resonant pulses

Ke Zhao, Ji‐Cai Liu, Chuan‐Kui Wang +1 more

The propagation of ultrashort pulses in a generalized two- level system, consisting of permanent dipole moments, is simulated by solving the full Maxwell - Bloch equations. Special attention has be ...

Jamal T. Manassah

Fan Xi-jun

In the cases of one-photon resonance and complete non-resonance, the effects of the relative carrier-envelope phase(RCEP) φ on pulse form and spectra characteristics of two-color ultrashort laser pulses in a Ξ-type three-level atomic medium are investigated by using numerical simulation.The results show that in the single-photon resonance case the RCEP has evident control role of profile and spectral characteristic of the two-color pulses.The RCEP can decide the amplitude, propagating velocity,pulse splitting case and the number of sub-pulses.When φ=0,the pulse does not split, and the shape and intensity of the pulse keep basically unchanged during the process of propagation.In the case of complete non-resonance, the pulse splitting doesn′t arise again, and the supercontinuum with frequency range much larger than that in the one-photon case can be obtained.Although the effects of RCEP on pulse shape and spectral property are not as strong as those in the one-photon resonance case, varying φ can still make frequency range and intensity distribution at different frequencies vary obviously.When φ=0, the supercontinuum with wider spectral range, better continuity and stronger intensity of high frequency components can be obtained.

Michael D. Crisp

Hongchuan Du, Bitao Hu

We present a theoretical study of isolated attosecond pulse generation with a multicycle chirped and chirped-free two-color field. We show that the bandwidth of the extreme ultraviolet supercontinuum can be extended by combining a multicycle chirped pulse and a multicycle chirped-free pulse. Also, the broadband supercontinuum can still be generated when the macroscopic effects are included. Furthermore, the macroscopic effects can ameliorate the temporal characteristic of the broadband supercontinuum of the single atom, and eliminate the modulations of the broadband supercontinuum. Thus a very smooth broadband supercontinuum and a pure isolated 102-as pulse can be directly obtained. Moreover, the structure of the broadband supercontinuum can be steadily maintained for a relative long distance after a certain distance.