Coherent response of the electronic system driven by non-interfering laser pulses.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35680865.
- Also identified by DOI 10.1038/s41467-022-30768-9 and PMC identifier 9184506.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The strength of light-matter interaction in condensed matter is fundamentally linked to the orientation and oscillation strength of the materials' optical transition dipoles. Structurally anisotropic materials, e.g., elongated molecules, exhibit optical transition dipoles with fixed orientations that govern the angular-dependent light-matter interaction. Contrary, free electron-like metals should exhibit isotropic light-matter interaction with the light fields dictating the orientation of the optical transition dipoles. Here, we demonstrate that an anisotropic direction of the optical transition dipoles even exists in highly free electron-like noble metal surfaces. Our time- and phase-resolved photoemission experiment reveals coherent interference effects on the (110)-oriented silver surface after optical excitation with two non-interfering cross-polarized pulses. We explain this coherent material response within the density matrix formalism by an intrinsic coupling of the non-interfering light fields mediated by optical transition dipoles with fixed orientations in silver.