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arXiv · 2411.08855

Ultrafast pump-probe phase-randomized tomography

Filippo Glerean·Enrico Maria Rigoni·Giacomo Jarc·Shahla Yasmin Mathengattil·Angela Montanaro·Francesca Giusti·Matteo Mitrano·Fabio Benatti·Daniele Fausti
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Abstract

Measuring fluctuations in matter's low energy excitations is the key to unveil the nature of the nonequilibrium response of materials. A promising outlook in this respect is offered by spectroscopic methods that address matter fluctuations by exploiting the statistical nature of light-matter interactions with weak few-photon probes. Here we report the first implementation of ultrafast phase randomized tomography, combining pump-probe experiments with quantum optical state tomography, to measure the ultrafast non-equilibrium dynamics in complex materials. Our approach utilizes a time-resolved multimode heterodyne detection scheme with phase-randomized coherent ultrashort laser pulses, overcoming the limitations of phase-stable configurations and enabling a robust reconstruction of the statistical distribution of phase-averaged optical observables. This methodology is validated by measuring the coherent phonon response in $\alpha$-quartz. By tracking the dynamics of the shot-noise limited photon number distribution of few-photon probes with ultrafast resolution, our results set an upper limit to the non-classical features of phononic state in $\alpha$-quartz and provide a pathway to access nonequilibrium quantum fluctuations in more complex quantum materials.

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Filippo Glerean, Enrico Maria Rigoni, Giacomo Jarc, Shahla Yasmin Mathengattil, Angela Montanaro, Francesca Giusti, Matteo Mitrano, Fabio Benatti, Daniele Fausti. 2024-11-13. Ultrafast pump-probe phase-randomized tomography. https://doi.org/10.1038/s41377-025-01789-y

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