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While interferometric methods exist for classifying vortex states of light, these techniques usually require destroying the beam of interest to determine the light’s OAM. A recent two-color pump-probe experiment employed strong field ionization and beam sculpting to classify vortex beams. Here, we propose an alternative strong-field method for distinguishing OAM states of light which does not require beam sculpting and instead utilizes a noncollinear terahertz standing wave to probe ionized electrons. We then use classical trajectory Monte Carlo (CTMC) methods to simulate strong-field ionization of helium under this configuration with the terahertz field both on and off. We find that the resulting electron momenta distributions can be used to extract the OAM of the beam, as long as the vortex beam spot size does not exceed 1/4 the terahertz pulse’s wavelength.
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Space-dependent photoelectron dynamics driven by intense vector vortex beams
Vortex beams are exotic states of classical light fields that contain orbital angular momentum (OAM) due to their space-dependent phases. While the experimental realization of intense low-frequency optical vortices has led to the discovery and application of OAM conservation in high-harmonic generation, there is not a comparable signature of light's OAM on photoelectrons. Here we propose using a linear combination of vortex modes, referred to as a vector vortex beam, for strong-field ionization of atoms. We then demonstrate that the input vortex beam's position-dependent phase can be obtained from the resulting electron momentum distribution following strong-field ionization. We validate this method by performing classical trajectory Monte Carlo simulations and comparing momentum distributions corresponding to different ionization locations within the beam profile, demonstrating that one can unambiguously determine the ionizing radiation's OAM index. These results are suitable for the added control offered by vortex light compared to Gaussian or plane-wave radiation in intense light-matter interactions.
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- Award ID(s):
- 2208040
- PAR ID:
- 10694921
- Publisher / Repository:
- Physical Review A
- Date Published:
- Journal Name:
- Physical Review A
- Volume:
- 111
- Issue:
- 4
- ISSN:
- 2469-9926
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1103/PhysRevA.111.L041102
