Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium response of materials.A promising outlook in this respect is offered by spectroscopic methods that a...Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium 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 inα-quartz.By tracking the dynamics of the shot-noise limited photon number distribution of fewphoton probes with ultrafast resolution,our results set an upper limit to the non-classical features of phononic state inα-quartz and provide a pathway to access non-equilibrium quantum fluctuations in more complex quantum materials.展开更多
基金supported by the European Research Council through the project INCEPT(grant agreement no.677488)D.F.,E.M.R.,A.M.,and G.J.acknowledge the support of the Gordon and Betty Moore Foundation through the grant(CENTQC).
文摘Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium 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 inα-quartz.By tracking the dynamics of the shot-noise limited photon number distribution of fewphoton probes with ultrafast resolution,our results set an upper limit to the non-classical features of phononic state inα-quartz and provide a pathway to access non-equilibrium quantum fluctuations in more complex quantum materials.
