Development of High-Repetition-Rate Liquid Plasma Mirrors for TW and PW Laser Systems

High-repetition-rate (HRR) high-intensity lasers show promise for applications in inertial fusion energy research, and the development of high-dose ion beam and x-ray sources, but performance is fundamentally limited by their intensity contrast. As energy and intensity increases, prepulses can pre-expand targets, reducing reliability, reproducibility, and flexibility in target thickness. Plasma mirrors improve temporal contrast by reflecting only the high-intensity portion of the pulse. However, conventional plasma mirrors are single-use and not practical for HRR experiments. HRR plasma optics require targets that refresh quickly, produce minimal debris, and are stable in vacuum. Liquid sheet targets meet this criteria and have been previously used in proton beam generation and plasma optics [1-2]. For micron-scale beam spots, liquid sheet plasma mirrors have been demonstrated to improve temporal contrast by a factor of 690 by utilizing the etalon-like anti-reflection properties of thin liquid sheets [2]. In this work, we present the design and development of a converging nozzle geometry to produce thin, stable liquid sheets compatible with TW and PW lasers, with predicted contrast improvements of 100-1000x [3-4], suitable for staging laser-plasma accelerator systems.

[1] F. Treffert, Phys. Plasmas 29, 12 (2022).

[2] K. M. George, High Power Laser Sci. Eng. 7, 50 (2019).

[3] B. Ha, Phys. Rev. Fluids 3, 114202 (2018).

[4] C. J. Crissman, Lab on a Chip 7, 1365 (2022).