Attosecond Pulses: The Three-Step Model of High-Harmonic Generation (2D)

This 2D canvas simulator visualises the physical mechanism behind the 2023 Nobel Prize in Physics by numerically integrating the classical electron trajectory in an oscillating laser field, step by step, rather than using a closed-form solution: an intense field tunnel-ionises an atom, Newton's second law genuinely accelerates the freed electron back and forth, and when the electron's position numerically returns through the parent ion the engine flags a recollision and computes the kinetic energy gained. Adjust the driving laser's peak field and wavelength, pick a target gas to set its ionization potential, and drag the birth-phase slider to explore how the emission energy depends on exactly when, within the optical cycle, the electron tunnels free — while a live return-energy-vs-ionization-phase chart, built from a fine numerical sweep over birth phase, traces out the famous I_p + 3.17·U_p harmonic cutoff law that sets the shortest attosecond pulses reachable at a given intensity.