Theoretical study of single attosecond pulse generation with a three-colour laser field

Abstract

We present a method of producing single attosecond pulses by using a few-cycle (5 fs) driving pulse with two additional weak control pulses. We discuss how single attosecond pulses produced from high-order harmonic generation processes in a synthesized three-colour laser field are similar to those processes in a much shorter single-colour laser field. Based on the high-order harmonic spectrum, classical ionizing and returning energy maps, time–frequency maps and time profiles of the attosecond pulses, the actions of the synthesized three-colour laser field are analogous to a 3 fs field although some differences still exist, and our method is proved to be a potential way to reduce the attosecond pulse duration from high-order harmonic generation with a currently available ultrafast laser source instead of a shorter pulse.

Quantum path control on the harmonic emission in the presence of a terahertz field

“…In our calculations, the HHG and the attosecond pulse can be investigated by solving the time-dependent Schrödinger equation (TDSE) [30][31][32][33][34][35][36][37][38] based on single-active electron approximation. In the dipole approximation and the length gauge, the TDSE is given by,…”

Single quantum path control by a fundamental chirped pulse combined with a subharmonic control pulse

“…For the chirp-free case ( Fig. 2(b)), there are three main peaks on the recombination energy map, which are caused by the three times recollisions [19,34,45,46] marked as M 1 , M 2 and M 3 in the profiles of the laser fields in Fig. 2(a) and (d); the maximum peak value is the 78th order harmonic corresponding to 119 eV, in quantitative agreement with the quantum result and the famous cutoff energy rule I p + 3.17U p (U p = E 2 /4ω 2 is the ponderomotive energy of the free electron).…”

“…In our numerical calculations, the HHG and the attosecond pulse generations can be investigated by solving the time-dependent Schrödinger equation (TDSE) [34][35][36][37]. In the dipole approximation and the length gauge, the TDSE is given by,…”

Low-energy structure in the ionization of argon: Comparison of experiment with theory

“…[17][18][19][20][21][22][23][24][25][26][27][28] In the dipole approximation and the length gauge, the TDSE is given by (atomic units are used throughout this paper unless stated otherwise)…”