Quantum Estimation in Strong Fields: in situ ponderomotive sensing

Abstract

We develop a new framework to optimize and understand uncertainty from in situ strong field measurements of laser field parameters. We present the first derivation of quantum and classical Fisher information for an electron undergoing strong-field ionization. This is used for parameter estimation and to characterize the uncertainty of the ponderomotive energy, directly proportional to laser intensity. In particular, the quantum and classical Fisher information for the momentum basis displays quadratic scaling over time. This can be linked to above-threshold ionization interference rings for measurements in the momentum basis and to the `ponderomotive phase' for the `ideal' quantum measurements. Preferential scaling is found for increasing laser pulse length and intensity. We use this to demonstrate for in situ measurements of laser intensity, that high resolution momentum spectroscopy has the capacity to reduce the uncertainty by over $25$ times compared to measurements employing the ionization rate, while using the `ideal' quantum measurement would reduce it by a further factor of $2.6$. A minimum uncertainty of the order $2.8\times 10^{-3}\%$ is theorized for this framework. Finally, we examine previous in situ measurements formulating a measurement that matches the experimental procedure and suggest how to improve this.

16 pages, 8 figures, 4 tables, 51 equations

References in corpus (4)

• Quantum-enhanced optical phase tracking
• Attoclock revisited on electron tunnelling time
• Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance
• Accurate in situ Measurement of Ellipticity Based on Sub-cycle Ionization Dynamics

Cited by in corpus (5)

• Entanglement of Orbital Angular Momentum in Non-Sequential Double Ionization
• Impact of the continuum Coulomb interaction in quantum-orbit-based treatments of high-order above-threshold ionization
• Controlling quantum effects in enhanced strong-field ionisation with machine-learning techniques
• Femtosecond pulse parameter estimation from photoelectron momenta using machine learning
• Unravelling inter-channel quantum interference in below-threshold nonsequential double ionization with statistical measures