• High Power Laser Science and Engineering
  • Vol. 9, Issue 2, 02000e25 (2021)
Fumika Isono1、2、*, Jeroen van Tilborg1, Samuel K. Barber1, Joseph Natal1、2, Curtis Berger1、2, Hai-En Tsai1, Tobias Ostermayr1, Anthony Gonsalves1, Cameron Geddes1, and Eric Esarey1
Author Affiliations
  • 1Lawrence Berkeley National Laboratory, Berkeley, CA, USA
  • 2University of California, Berkeley, CA, USA
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    Abstract

    Controlling the delivery of multi-terawatt and petawatt laser pulses to final focus, both in position and angle, is critical to many laser applications such as optical guiding, laser–plasma acceleration, and laser-produced secondary radiation. We present an online, non-destructive laser diagnostic, capable of measuring the transverse position and pointing angle at focus. The diagnostic is based on a unique double-surface-coated wedged-mirror design for the final steering optic in the laser line, producing a witness beam highly correlated with the main beam. By propagating low-power kilohertz pulses to focus, we observed spectra of focus position and pointing angle fluctuations dominated by frequencies below 70 Hz. The setup was also used to characterize the excellent position and pointing angle correlation of the 1 Hz high-power laser pulses to this low-power kilohertz pulse train, opening a promising path to fast non-perturbative feedback concepts even on few-hertz-class high-power laser systems.

    1 Introduction

    High-power laser systems, targeting science at relativistic laser intensities ($>{10}^{18}$ W/cm${}^2$), are now routinely employed at laboratories all over the world, ranging from peak powers of tens of terawatts to multi-petawatt and beyond[14]. Such high peak power is enabled by concentrating joules of laser energy into femtosecond-duration pulses via chirped pulse amplification[5]. When focused to micrometer-sized spots, the peak intensity reaches a regime where matter is easily ionized and the electrons quiver at relativistic speeds. Nonlinear laser–plasma processes can then be accessed, driving applications such as laser–plasma acceleration (LPA; where plasma electrons are accelerated to gigaelectronvolt-level energies over distances of just centimeters[6]), LPA-based light sources[710], plasma-based X-ray lasers[11], and ion acceleration from solid targets[12], among others.

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    Fumika Isono, Jeroen van Tilborg, Samuel K. Barber, Joseph Natal, Curtis Berger, Hai-En Tsai, Tobias Ostermayr, Anthony Gonsalves, Cameron Geddes, Eric Esarey. High-power non-perturbative laser delivery diagnostics at the final focus of 100-TW-class laser pulses[J]. High Power Laser Science and Engineering, 2021, 9(2): 02000e25
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    Category: Research Articles
    Received: Dec. 16, 2020
    Accepted: Feb. 26, 2021
    Published Online: Aug. 3, 2021
    The Author Email: Fumika Isono (JvanTilborg@lbl.gov)