This project focuses on a fundamental physics characteristic of light - its orbital angular momentum (OAM). A signature of a laser beam with OAM is a twisted wave-front that is shaped as a helix. The role of OAM in high-intensity laser-plasma interactions is still poorly understood and this project will address it through a dedicated computational research program that couples to experiments at flagship European laser facilities. The Extreme Light Infrastructure (ELI) laser facilities located in Romania and in the Czech Republic have some of the most powerful lasers in the world. The project will explore new methods for creating high-intensity helical laser pulses and new methods that facilitate the exchange of OAM between a laser pulse and a plasma. Specifically, the aim is to determine the impact of the OAM exchange on laser-driven ion acceleration via computational modeling, and to experimentally test the results of the models at the ELI facilities. This exploratory research will pave the way towards a long term research program of utilizing helical light beams for novel nuclear physics and strong-field experiments at the ELI-Nuclear Physics (ELI-NP) facility in Romania.
In the context of high-intensity laser-matter interactions, most of the laser improvements have been focused on increasing power, on-target intensity, total energy, and the contrast of the compressed pulse. There is however another fundamental characteristic of polarized light - its angular momentum. The orbital angular momentum is associated with an azimuthal phase dependence, so it is independent of the polarization and can be significantly enhanced by generating a laser beam with twisted wave-fronts. This project is a collaborative program with an aim to explore the frontiers of light-matter interaction by pushing the OAM carrying helical photon beams to relativistic intensities and investigating their exchange of angular momentum with relativistic plasmas. This project will combine theoretical and simulation research with a dedicated experimental program at the new 1 petawatt (PW) CETAL laser and 1 PW and 10 PW ELI-NP laser facilities in Romania. The project will determine the impact of the OAM exchange on laser-driven ion acceleration and the conditions for effectively generating a twisted pondermotive force by short laser pulses. The latter generates a long-lasting volumetric magnetic field in a plasma suitable for controlling charged particle transport.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
