Abnormal relativistic emission generated by strong interaction between laser and plasma reflector

The interaction between strong laser pulses and plasma mirrors has been a focus of recent physical research, as they generate interesting effects. Experiments have shown that these interactions can generate a nonlinear physical process called high-order harmonics, characterized by emitting extreme ultraviolet radiation and brief flashes of laser light.

Researchers from the Czech Extreme Light Infrastructure ERIC and Osaka University in Japan have recently discovered surprising transitions that occur during the interaction between strong laser pulses and plasma mirrors. This transformation is marked by the anomalous emission of coherent XUV radiation, as outlined in a paper published in the Physical Review Letters.

"The relativistic oscillating mirror is a fascinating concept with enormous potential for strong attosecond pulses and bright XUV generation," one of the researchers conducting this study, Marcel Lamač, told Phys.org.

We are re examining some assumptions from previous work and found that strong self modulation occurs during strong laser mirror interactions, altering the characteristics of surface emitted extreme ultraviolet radiation, which can then propagate abnormally along the surface.

Lamač and his colleagues discovered this interesting finding while testing predictions of previous work in the field. The team conducted various numerical and multi-dimensional intracellular particle simulations with extremely high resolution, with the aim of better understanding the interactions between electrons and ions in the interaction process between solid density plasma and strong laser.

"One of the most direct results of our work is that we must be very careful in target selection and plasma pre control to prevent loss of spatiotemporal coherence in reflected high harmonics," said Lamač.

Due to our discovery that relativistic instability modulation emission may be more effective than reflection of high harmonics within the XUV range, this emission can also be considered a potential efficient XUV source, which requires precise control of experimental conditions to achieve high yields of XUV emission.

The emission of XUV radiation observed by Lamač and his colleagues in simulations exhibits unique and interesting characteristics. Specifically, researchers have found that this coherent radiation propagates parallel to the surface of the plasma mirror. Further calculations link this anomalous emission to the relativistic electron nanobeam oscillations driven by lasers, which originate from the instability of the plasma surface.

"We believe that there is an interesting potential in potentially controlling this mirror self modulation, where enhanced coherence can be achieved in the initial stage of surface instability, resulting in more narrowband coherent XUVs," added Lamač.

Lamač and his collaborators recently collected new insights into the physical processes generated by the interaction between strong laser pulses and plasma mirrors. The simulation results of researchers may soon pave the way for further exploration of the anomalous emissions they observe, potentially bringing new interesting discoveries.

Source: Laser Net