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arXiv · 1610.02007

Self-aligning concave relativistic plasma mirror with adjustable focus

Hai-En Tsai·Alexey V. Arefiev·Joseph M. Shaw·David J. Stark·Xiaoming Wang·Rafal Zgadzaj·M. C. Downer
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Abstract

We report an experimental-computational study of the optical properties of plasma mirrors (PMs) at the incident laser frequency when irradiated directly at relativistic intensity (1e18 < I_0 < 1e19 W/cm^2) by near-normally incident (4 degree), high-contrast, 30 fs, 800 nm laser pulses. We find that such relativistic PMs are highly reflective (0.6 to 0.8), and focus a significant fraction of reflected light to intensity as large as 10I_0 at distance f as small 25 microns from the PM, provided that pre-pulses do not exceed 1e14 W/cm^2 prior to 20 ps before arrival of the main pulse peak. Particle-in-cell simulations show that focusing results from denting of the reflecting surface by light pressure combined with relativistic transparency, and that reflectivity and f can be adjusted by controlling pre-plasma length L over the range 0.5 < L < 3 microns. Pump-probe reflectivity measurements show the PM's focusing properties evolve on a ps time scale.

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Hai-En Tsai, Alexey V. Arefiev, Joseph M. Shaw, David J. Stark, Xiaoming Wang, Rafal Zgadzaj, M. C. Downer. 2016-10-06. Self-aligning concave relativistic plasma mirror with adjustable focus. https://doi.org/10.1063/1.4973432

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