Electronic Currents and Magnetic Fields in H2+ Induced by Coherent Resonant Bichromatic Circularly Polarized Laser Pulses: Effects of Orientation, Phase, and Helicity

Abstract

We theoretically study pulse phase and helicity effects on ultrafast magnetic field generation in intense bichromatic circularly polarized laser fields. Simulations are performed on the aligned molecular ion H2+ from numerical solutions of corresponding time-dependent Schrödinger equations. We demonstrate how electron coherent resonant excitation influences the phase and helicity of the optically induced magnetic field generation. The dependence of the generated magnetic field on the pulse phase arises from the interference effect between multiple excitation and ionization pathways, and is shown to be sensitive to molecular alignment and laser polarization. Molecular resonant excitation induces coherent ring electron currents, giving enhancement or suppression of the phase dependence. Pulse helicity effects control laser-induced electron dynamics in bichromatic circular polarization excitation. These phenomena are demonstrated by a molecular attosecond photoionization model and coherent electron current theory. The results offer a guiding principle for generating ultrafast magnetic fields and for studying coherent electron dynamics in complex molecular systems.

Quantum control of ultrafast magnetic field in H32+ molecules by tricircular polarized laser pulses

“…( 6) can be simplified to [note that the time-dependent term (1/c)∂ 𝑗 (𝑟,t) /∂t in Eq. ( 6) is usually found to be negligible [23,25,33] ]…”

“…Actually, for resonance excitation, the excited state transition probability is determined by the intrinsic transition dipole of molecules and the electric field strength and is insensitive to the pulse phase. [23]…”

“…[16,17] Recently, based on an attosecond time scale, a new attosecond magnetization has been realized. [18][19][20][21][22][23][24][25] Much effort has been devoted to investigating the dependence of ultrafast magnetic field generation from coherent electronic currents in H + 2 on the laser parameters and molecular alignment. [19,23,25] Moreover, the generation of ultrafast magnetic fields from the point of view of resonance excitation of H 2+ 3 molecules by monochrome CP laser pulses has also been explored.…”

Electronic ring current and magnetic field generation induced by current-carrying states of ring molecules in intense fields

“…The breakthrough of laser pulses [1][2][3][4] ranging from the subfemtosecond toward the attosecond time domain has opened a new door for investigating atomic and molecular dynamics on ultra-short time scales [5][6][7][8][9]. Recently, it has been reported that electronic currents and magnetic fields can be effectively induced by attosecond UV pulses in molecules [10,11]. Such light-induced ultrashort magnetic pulses have shown potential applications in many fields, such as molecular paramagnetic bonding [12], demagnetization processes [13] and magnetic data recording [14].…”

All-Optical Polarization Manipulation Through Orbital Polarization Holography

“…Transfer of optical angular momentum (AM) has been proposed in the last few decades as an effective tool to achieve optical manipulation, quantum communication and so on [1,2]. Generally, there are two kinds of AM carried by light, spin AM (SAM) and orbital AM (OAM).…”