Anomalous Magnetization Dynamics After Dual Optical Excitation

Le résumé fourni par la source

Ultrafast optical excitation is widely used to manipulate electronic and magnetic properties of materials on femtosecondtimescales. In this study, we investigate the response of copper to circularly polarized femtosecond pulses using time-resolvedmagneto-optical Kerr effect measurements. We compare the dynamics induced by single-pulse excitation with those resultingfrom a dual-pump configuration, in which two pulses arrive simultaneously from different directions. Although the individualcontributions of the two pumps are similar when applied separately, their combined effect leads to a marked change in thespin/orbital dynamics. Specifically, we observe an approximately 2.5-fold increase in the decay time of the spin/orbital imbalancesignal under dual-pump excitation. This result indicates that the joint action of two optical pulses can qualitatively alter therelaxation pathways in the system, beyond a simple additive response. The observed behavior highlights a previously unexploredregime of light-induced dynamics and suggests new strategies for controlling ultrafast processes in solids.

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