Controlling the atomic-orbital-resolved photoionization for neon atoms by counter-rotating circularly polarized attosecond pulses

Abstract

We theoretically investigate the atomic-orbital-resolved vortex-shaped photoelectron momentum distributions (PMDs) and ionization probabilities by solving the two-dimensional time-dependent Schrödinger equation (2D-TDSE) of neon in a pair of delayed counter-rotating circularly polarized attosecond pulses. We found that the number of spiral arms in vortex patterns is twice the number of absorbed photons when the initial state is the ψm=±1 state, which satisfy a change from c2n+2 to c2n (n is the number of absorbed photons) rotational symmetry of the vortices if the 2p state is replaced by 2p+ or 2p− states. For two- and three-photon ionization, the magnetic quantum number dependence of ionization probabilities is quite weak. Interestingly, single-photon ionization is preferred when the electron and laser field corotate and ionization probabilities of 2p− is much larger than that of 2p+ if the proper time delay and wavelength are used. The relative ratio of ionization probabilities between 2p− and 2p+ is insensitive to laser peak intensity, which can be controlled by changing the wavelength, time delay, relative phase and amplitude ratio of two attosecond pulses.

Photoelectron momentum distributions of Ne and Xe dimers in counter-rotating circularly polarized laser fields

“…Meanwhile, we can see that at t = 17.18 o.c., i.e., near the end of laser pulses, the We also describe the photoionization process by the ultrafast photoionization model, the derivation process of Xe dimer is the same as the Eqs. ( 10)- (19) for Ne dimer, the initial state of Xe dimer is of gerade parity, the wavefunction is given by Ψ 5pσ g (𝑟) = (1/ √ 2)[Ψ 5p (𝑟 − 𝑅 (Xe−Xe) /2) −Ψ 5p (𝑟 + 𝑅 (Xe−Xe) /2)], which is a linear combination of 5p atomic orbital that are located at ±R (Xe−Xe) /2. By taking ultrafast photoionization model into account, the transition amplitude can thus be rewritten as…”

“…The photoelectron momentum distributions (PMDs) and photoelectron angular distributions (PADs) of atoms and molecules contain valuable information about the electron dynamics, which have attracted great attention of researchers over the past few years. [19][20][21] Besides, they are also important for detecting electron dynamics and the structure of atoms and molecules.…”

Electron vortices generation of photoelectron of H2+ by counter-rotating circularly polarized attosecond pulses

“…As the time delay expands, the spiral arms in MF-PMDs become more elongated and slender. [48] In addition, as the time delay increases, the yield of the y-component laser field will continue to grow, and the yield of perpendicular geometry will become more pronounced. the vortex structure still exists, but the two arms on the x axis diminish, and connect to the other arms.…”

Electron vortex generations in photoionization of hydrogen atoms by circularly-polarized chirped attosecond pulses

“…The generation of vortex-shaped photoelectron wave packets in the photoionization of helium atoms [13,28] and hydrogen molecular ions [29] has been proposed by employing timedelayed counter-rotating circularly polarized attosecond pulses. In addition to the time delay, researchers have also explored the control of other laser parameters, such as the carrier-envelope phase (CEP) [17,27], relative optical phase [25,30], polarization state [13,23,28,31,32], orbital symmetry [33,34], and chirp [35]. Moreover, vortices have not only been observed in photoionization but also in photodissociation [29] and photodetachment [36,37].…”