Speaker
Description
A plasma mirror is formed when an intense laser pulse ionizes a solid target, creating an overdense plasma that reflects light specularly. In the relativistic regime($I \gtrsim 10^{18}Wcm^{-2}$ at $\lambda=800nm$), plasma mirrors generate high-order harmonics extending into the EUV and soft x-ray range. In the Coherent Synchrotron Emission (CSE) regime, relativistically driven electron nanobunches follow synchrotron-like trajectories and emit coherent, broadband radiation in attosecond bursts.
Control over the polarization of this emission is critical for applications such as magnetic circular dichroism and chiral spectroscopy. Here, we experimentally demonstrate tunable polarization of low-order harmonics by varying the polarization state of the driving laser($\lambda_0 = 800nm$, $\tau = 25fs$, $I = 10^{19}Wcm^{-2}$). Using Stokes polarimetry, we show continuous control from linear to circular polarization without significant loss of conversion efficiency.
Particle-in-cell simulations show strong agreement with experimental results for low-order harmonics and predict similar polarization trends at higher orders in the EUV. These results establish plasma mirrors as a promising route toward high-intensity, polarization-tunable EUV and attosecond sources.
This work was supported by the NSF Grants No. PHY 2206711, PHY 2512131, DOE Grant DE-SC0025497, and by the Gordon and Betty Moore Foundation, grant DOI 10.37807/GBMF12255.
| Working group | WG6 |
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