Self-Referencing Spectral Interferometric Probing of the Onset Time of Relativistic Transparency in Intense Laser-Foil Interactions
| Autor: | Robbie Wilson, S. D. R. Williamson, David Neely, A. Higginson, M. J. Duff, Ross Gray, Bruno Gonzalez-Izquierdo, M. King, Nicola Booth, S. J. Hawkes, Z. E. Davidson, Paul McKenna |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
business.industry General Physics and Astronomy 02 engineering and technology Radiation 021001 nanoscience & nanotechnology Laser 01 natural sciences law.invention Ion Interferometry Optics Transition radiation Physics::Plasma Physics law Harmonics 0103 physical sciences Irradiation 010306 general physics 0210 nano-technology business QC FOIL method |
| Zdroj: | Physical Review Applied. 14 |
| ISSN: | 2331-7019 2331-7043 |
| Popis: | Irradiation of an ultrathin foil target by a high intensity laser pulse drives collective electron motion and the generation of strong electrostatic fields, resulting in ultrabright sources of high-order harmonics and energetic ions. The ion energies can be significantly enhanced if the foil undergoes relativistic self-induced transparency during the interaction, with the degree of enhancement depending in part on the onset time of transparency. We report on a simple and effective approach to diagnose the time during the interaction at which the foil becomes transparent to the laser light, providing a route to optically controlling and optimizing ion acceleration and radiation generation. The scheme involves a self-referencing approach to spectral interferometry, in which coherent transition radiation produced at the foil rear interferes with laser light transmitted through the foil. The relative timing of the onset of transmission with respect to the transition radiation generation is determined from spectral fringe spacing and compared to simultaneous frequency-resolved optical gating measurements. The results are in excellent agreement, and are discussed with reference to particle-in-cell simulations of the interaction physics and an analytical model for the onset time of transparency in ultrathin foils. |
| Databáze: | OpenAIRE |
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