Macroscopic aspects of attosecond pulse generation

TLDR

Attosecond pulses are produced by a macroscopic ensemble of ionizing atoms driven by a focused laser pulse through high‑harmonic generation, a process governed by the interplay of microscopic laser–atom interaction and macroscopic ionization and phase‑matching effects. This review seeks to fully understand how attosecond pulses reach a target for characterization and use in experiments. It examines the propagation and arrival of these pulses at the target, considering macroscopic effects that shape their temporal and spatial profiles. Simultaneous solutions of the time‑dependent Schrödinger equation and Maxwell wave equation reveal that macroscopic effects can be exploited to select specific attosecond pulses from the emitted radiation, allowing a clear separation of microscopic and macroscopic contributions.

Abstract

Attosecond pulses are generated by a macroscopic number of ionizing atoms interacting with a focused laser pulse, via the process of high harmonic generation. The physics of their generation consists of an interplay between the microscopic laser–atom interaction and macroscopic effects due to ionization and phase matching in the nonlinear medium. In this review, we focus on a complete understanding of the way in which attosecond pulses arrive at a target where they can be characterized and used in an experiment. We discuss a number of results from calculations of attosecond pulse generation obtained by simultaneous solution of the time-dependent Schrödinger equation and the Maxwell wave equation. These results, which allow for a clean separation of microscopic and macroscopic factors, illustrate how macroscopic effects are used to select attosecond pulses from the radiation that is emitted by atoms interacting with a strong laser field.