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arXiv · 2508.07500

Ionization rate vs. laser intensity determined from ion count vs. peak intensity due to neutral gas exposure to an 800 nm ultrashort pulsed laser

Edward L. Ruden
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Abstract

The optical cycle-averaged ionization rate of Ar, O$_2$, and N$_2$ vs. local instantaneous laser intensity $I$ for linear polarized 800 nm light is determined up to approx. 300 TW/cm$^2$ by numerically inverting published time-of-flight ion spectrometer data. The published Ar$^+$ collection efficiency of the microchannel plate (MCP) at the end of the spectrometer and its $I_0$ scale are recalibrated by fitting it to its high $I_0$ solution. The relative collection efficiencies of the other species are determined by published MCP cathode data. Results for O$_2$ are consistent with a reevaluation of published data used to determine its cross section $σ_8$ in the multiphoton (low $I$) regime.

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Edward L. Ruden. 2026-09-11. Ionization rate vs. laser intensity determined from ion count vs. peak intensity due to neutral gas exposure to an 800 nm ultrashort pulsed laser. https://arxiv.org/abs/2508.07500

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