Resonant x-ray difference frequency generation
Resonantly enhanced x-ray difference-frequency generation (re-XDFG) is a second-order nonlinear effect that involves illuminating a molecule with two-color x-ray pulses with photon energies O1 and O2. The energy difference $\Omega_1-\Omega_2$ is tuned to match an x-ray absorption edge of an atom in...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/400860 |
| Acceso en línea: | https://hdl.handle.net/2117/400860 https://dx.doi.org/10.1088/1361-6455/ad0f39 |
| Access Level: | acceso abierto |
| Palabra clave: | X-Rays Quantum optics X-ray nonlinear wave-mixing XFEL NEXAFS Ultrafast dynamics Raigs X Òptica quàntica Àrees temàtiques de la UPC::Física |
| Sumario: | Resonantly enhanced x-ray difference-frequency generation (re-XDFG) is a second-order nonlinear effect that involves illuminating a molecule with two-color x-ray pulses with photon energies O1 and O2. The energy difference $\Omega_1-\Omega_2$ is tuned to match an x-ray absorption edge of an atom in the molecule. We have numerically studied the re-XDFG effect considering different individual molecules in the gas phase using density functional theory calculations and have verified the non-centrosymmetric character of the target transitions. Two-level molecular systems with permanent dipoles are evaluated for the description of re-XDFG taking into account different two-color input pulse geometries. This innovative nonlinear x-ray methodology offers a means to measure the K-edge NEXAFS spectrum of light elements, such as carbon, nitrogen, or oxygen, in dense media using non-resonant x-rays. It can also be used to investigate chemical material dynamics that are inaccessible by linear spectroscopy. These findings enable the combination of atomic-scale structure with chemical specificity and the selective and local access to x-ray excitations using hard x-ray pulses. |
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