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The Oxford Atomic and Laser Physics webinar series welcomes Dr. Ramy Aboushelbaya (Oxford University).
For the past 30 years ever since the characterization of Laguerre-Gaussian modes, the science of the orbital angular momentum (OAM) of light has been continuously evolving. The OAM of light has found applications across a vast number of fields ranging from quantum information processing to classical communication and even to laser-plasma interactions. Nevertheless, despite the breadth of research into the OAM of light, its theoretical foundations have been the subject of an intriguing debate, concerning the split between the spin and orbital angular momenta of fundamental particles, that strikes at the core of some of physics’ most interesting open questions. Beyond the theoretical questions surrounding OAM, there are also, of course, experimental limitations that have prevented its interesting effects from being more thoroughly explored in high-energy density applications. These limitations are namely to do with the difficulty of the generation and characterization of high-intensity laser pulses which are carrying OAM.
I will be presenting various results which have borne out of research done at Oxford’s Atomic and Laser Physics department on the various applications of OAM-carrying high-power laser pulses. First, we show how the conservation of angular momentum leads to a coupling condition on the vacuum photon-photon scattering interaction which increases its detectability in experiments. This interaction, which was originally predicted by the pioneers of quantum field theory, has not yet been experimentally verified using real photons. The use of OAM modes along with the ever-increasing power available at laser facilities should allow for the first-even detection of this effect using laser pulses, opening the door for the exploration of other channels to vacuum polarization. Going then to a different regime of high-intensity laser interactions, we outline how the OAM modes of light can be used to control and potentially mitigate unwanted laser-plasma instabilities which are detrimental to inertial confinement fusion (ICF). Through the use of Particle-in-Cell (PIC) simulations, we show how these modes can affect the triggering of stimulated Raman scattering. Finally, we explore how the aforementioned experimental limitations can be circumvented by showcasing some recent experimental results that show efficient generation and characterization of high-intensity pulses carrying OAM.
Passcode: ALPhysics