Wätzel J., Blättermann A., Schulz D., Chiang C.T., and Berakdar J.

We study theoretically the transfer of the light field orbital angular momentum (OAM) to propagating electrons upon photoemission from quantum well states. Irradiation with a Laguerre-Gaussian mode laser pulse elevates the quantum well state into a laser-dressed Volkov state that can be detected in an angular and energy-resolved manner while varying the characteristics of the driving fields. We derive the photoemission cross section for this process using the S-matrix theory and illustrate how the OAM is embodied in the photoelectron angular pattern with the aid of numerical calculations. The results point to a new type of time-resolved spectroscopy, in which the electronic orbital motion is addressed exclusively, with the potential for a new insight in spin-orbitally or orbitally coupled systems.

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