Coherent Excitonic Quantum Beats in Time-Resolved Photoemission Measurements

Abstract

Coherent excitation of materials via ultrafast laser pulses can have interesting, observable dynamics in time-resolved photoemission measurements. The broad spectral width of ultrafast pump pulses can coherently excite multiple exciton energy levels. When such coherently excited states are probed by means of photoemission spectroscopy, interference between the polarization of different exciton levels can lead to observable coherent exciton beats. Here, we present the theoretical formalism for evaluating the Time- and Angle- Resolved Photoemission Spectra (tr-ARPES) arising from the coherently excited exciton states. We subsequently apply our formalism to a simple model example of hydrogenic exciton energy levels to identify the dependencies that control the quantum beats. Our findings indicate that the most pronounced effect of coherent quantum excitonic beats is seen midway between the excited exciton energy levels and the central energy of the pump pulse provides tunability of this effect.

8 pages, 5 figures

References in corpus (5)

• Electronic structure of the iron-based superconductor LaOFeP
• Theoretical description of time-resolved photoemission spectroscopy: application to pump-probe experiments
• Transient excitons at metal surfaces
• Ultrafast Angle-Resolved Photoemission Spectroscopy of Quantum Materials
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Cited by in corpus (6)

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• Analysis methodology of coherent oscillations in time- and angle-resolved photoemission spectroscopy
• Quantum beats of coherent 1s 2s excitons in two dimensional transition metal