Intensity control of a high-intensity laser pulses for optimising plasma acceleration schemes
Plasma-based particle accelerators have garnered significant interest due to their potential to revolutionize high-energy physics and medical applications. Laser-driven plasma accelerators (LPA) have demonstrated the ability to accelerate electrons to multi-GeV [1] and protons to 100’s MeV [2] energies in compact setups, offering a promising alternative to traditional accelerator technologies. However, significant challenges remain in controlling and optimising the laser-plasma interaction to achieve high efficiency, stable acceleration, and optimal beam quality.
The interaction between the laser pulse and the plasma is highly dependent on the spatial and temporal characteristics of the laser. The focal spot intensity profile plays a crucial role in determining the efficiency of energy transfer into the plasma and, ultimately, the acceleration process. Focal spot shaping has been shown to improve the performance of laser-plasma accelerators by optimising the coupling of laser energy into the plasma.
This project will involve the use and optimisation of a deformable mirror (adaptive optic system) along with custom phase plates to produce allow phase front control of intense laser beams. This can produce laser beams with unique properties such as modes with zero on-axis intensities which could be used for accelerating positrons in a wakefield accelerator [3], or even in controlling the group velocity of the laser pulse. Indeed, recent simulations with spatiotemporally controlled laser pulses have demonstrated laser pulses that can travel at exactly the vacuum speed of light (or even superluminally) [4] which can greatly enhance the acceleration witnessed by electrons in the plasma accelerator.
The project will involve a mixture of modelling of the unique laser pulses, and their effect on plasma accelerators, as well as implementation on the high rep-rate Zhi laser at the Blackett Laboratory.
[1] Põder, K., Wood, J. C., Lopes, N. C., Cole, J. M., Alatabi, S., Backhouse, M. P., Foster, P. S., Hughes, A. J., Kamperidis, C., Kononenko, O., Mangles, S. P. D., Palmer, C. A. J., Rusby, D., Sahai, A., Sarri, G., Symes, D. R., Warwick, J. R., & Najmudin, Z. (2024). Multi-GeV Electron Acceleration in Wakefields Strongly Driven by Oversized Laser Spots. Physical Review Letters, 132(19), 195001. https://doi.org/10.1103/PhysRevLett.132.195001
[2] Ziegler, T., Göthel, I., Assenbaum, S., Bernert, C., Brack, F. E., Cowan, T. E., Dover, N. P., Gaus, L., Kluge, T., Kraft, S., Kroll, F., Metzkes-Ng, J., Nishiuchi, M., Prencipe, I., Püschel, T., Rehwald, M., Reimold, M., Schlenvoigt, H. P., Umlandt, M. E. P., … Zeil, K. (2024). Laser-driven high-energy proton beams from cascaded acceleration regimes. Nature Physics 2024 20:7, 20(7), 1211–1216. https://doi.org/10.1038/s41567-024-02505-0
[3] Cao, G. J., Lindstrøm, C. A., Adli, E., Corde, S., & Gessner, S. (2024). Positron acceleration in plasma wakefields. In Physical Review Accelerators and Beams (Vol. 27, Issue 3). https://doi.org/10.1103/PhysRevAccelBeams.27.034801
[4] Sainte-Marie, A., Gobert, O., & Quéré, F. (2017). Controlling the velocity of ultrashort light pulses in vacuum through spatio-temporal couplings. Optica, 4(10), 1298. https://doi.org/10.1364/optica.4.001298
For further information please contact Prof Zulfikar Najmudin on z.najmudin@imperial.ac.uk.