An anomalous relativistic emission resulting from the intense interaction of lasers with plasma mirrors

The interactions between intense laser pulses and plasma mirrors have been the subject of several recent physics studies because of the interesting effects they produce. Experiments have revealed that these interactions can generate a nonlinear physical process called high-order harmonics, characterized by the emission of extreme ultraviolet (XUV) radiation and brief flashes of laser light (i.e. attosecond pulses).

Researchers from ERIC Light Infrastructure in Czechia and Osaka University in Japan recently discovered a surprising transition that occurs during interactions between intense laser pulses and plasma mirrors. This transition, marked by an anomalous emission of coherent XUV radiation, was described in an article published in Physical Examination Letters.

“Relativistic oscillating mirrors are a fascinating concept with great potential for intense attosecond pulse and bright XUV generation,” Marcel Lamač, one of the researchers who led the study, told Phys.org.

“We re-examined some of the assumptions made in previous work and found that strong self-modulation can occur during the intense laser-mirror interaction, changing the properties of the extreme ultraviolet (XUV) radiation emitted by the surface, which can then spread unnaturally along the surface. surface.”

Lamač and colleagues’ interesting discovery was made while they were testing predictions from previous work in this area. The team performed various multidimensional numerical simulations of particles in cells at extremely high resolutions, with the aim of better understanding the interaction between electrons and ions when solid density plasmas interact with intense lasers.

“One of the most immediate implications of our work is that great care must be taken in target selection and pre-plasma control to avoid loss of spatiotemporal coherence in the reflected high harmonics,” Lamač said.

“Since we found that instability-modulated relativistic emission can be more effective than reflected high harmonics in the XUV range, this emission can also be considered a potentially very efficient XUV source, which would require such precise control experimental conditions to obtain high XUV emission efficiency.

The XUV radiation emission observed by Lamač and his colleagues in their simulations has a unique and interesting property. More specifically, the researchers discovered that this coherent radiation propagates parallel to the surface of the plasma mirror. Further calculations linked this anomalous emission to laser-induced oscillations of relativistic electron nanoclusters originating from plasma surface instability.

“We believe there is interesting potential in the potential control of this mirror self-modulation, where improved coherence could be achieved for narrower band coherent XUV generation in the early stages of surface instability,” added Lamač.

This recent work by Lamač and his collaborators has provided new information on the physical processes resulting from the interaction between intense laser pulses and plasma mirrors. The results of the researchers’ simulations could soon pave the way for other studies exploring the anomalous emissions they observed, potentially leading to interesting new discoveries.

© 2023 Science X Network