GoLP Seminar: lectured by Slava Smartsev
Slava Smartsev will be holding a seminar on 12 June 2024, organised by the Group of Lasers and Plasmas at IPFN.
Implementing and Measuring Spatio-Temporal Couplings toward Dephasingless Laser-Wakefield Acceleration, by Slava Smartsev, Laboratoire d’Optique Appliquée, France
12 June, 2024, 11 a.m.
Venue: Anfiteatro PA1, Ed. Matemática, IST
Abstract
With the steady progress of femtosecond, multi-terawatt pulses, high-power laser systems have become essential tools in scientific research. In particular, such systems, when coupled with a plasma target, can generate high-quality electron beams. Spatial sculpting of the plasma target’s density profile is a well-known and widely used method to optimize the resultant electron beams. More recently, much effort has been devoted to opening an additional experimental degree of freedom through intricate space-time sculpting of the laser beam. This is accomplished by manipulating the Spatio-Temporal Couplings (STCs) of the laser, which promises to further enhance the performance of laser-plasma accelerators.
I will present a particular laser space-time shaping technique based on a special optical element called the 'axiparabola,' a long-focal-depth reflective optical element that produces a quasi-Bessel beam [1]. By additionally manipulating the spatio-temporal profile of the beam focused by the axiparabola, it is possible to alter the dynamics of energy deposition onto the optical axis. This scheme can potentially overcome both the beam diffraction and the electron dephasing limitations of laser-wakefield acceleration [2,3]. I will present experimental measurements of the axial energy deposition velocity of the axiparabola and its dependence on the spatio-temporal beam profile [4].
Finally, I will present a recent and simple few-shot method to measure the general STCs of the laser [5]. This new method allows us to tap into information about the beam hidden inside seemingly random speckle patterns. Taken together, these advances enable accurate characterization and manipulation of the spatio-temporal behavior of the laser, allowing effective usage of this knob towards the goal of dephasingless laser-wakefield acceleration.
Bibliography:
[1] S. Smartsev et al. “Axiparabola: a long-focal-depth, high-resolution mirror for broadband high-intensity lasers,” Opt. Lett. 44, 3414-3417 (2019)
[2] C. Caizergues et al. “Phase-locked laser-wakefield electron acceleration,” Nat. Phot. 14, 475-479 (2020)
[3] J.P. Palastro et al. “Dephasingless Laser Wakefield Acceleration,” PRL 124, 134802 (2020)
[4] A. Liberman et al. “Use of spatiotemporal couplings and an axiparabola to control the velocity of peak intensity,” Opt. Lett. 49, 814-817 (2024).
[5] S. Smartsev et al. “Simple few-shot method for spectrally resolving the wavefront of an ultrashort laser pulse,” Opt. Lett. 49, 1900-1903 (2024).
