Laguerre–Gaussian (LG) beams carrying orbital angular momentum (OAM) of light have been shown to benefit a wide range of applications from optical manipulation, quantum information processing, and super-resolution imaging. Although OAM light beams have wide spread applications, the formal understanding of the light-matter interaction with such beams is a hotly debated topic that currently has many unanswered questions. From a spectroscopic viewpoint, a complete picture of the OAM light-matter interaction is crucial because, as recent theoretical work has suggested, the OAM content of LG beams may be exploited to probe typically inaccessible processes in atomic and molecular systems. Despite this unique potential of LG beams possessing OAM, surprisingly few experimental studies have been reported to compliment the theoretical treatments of OAM optical processes. To this end, we report measurements of the strong field ionization (SFI) by LG beams with a three-dimensional velocity map imaging (VMI) spectrometer. Specifically, LG beams produced in the near-infrared carrying different orbital angular momenta are used to ionize atoms and molecules over a wide range of intensities spanning the multiphoton and tunneling ionization regimes. The unique capability of the 3D VMI allows us to resolve the momentum distribution in the plane perpendicular to the phase singularity, where OAM-dependent effects are anticipated to be strongest. Our preliminary results exhibit weak OAM dependent effects in the photoelectron momentum distributions, suggesting the OAM nature of the light plays a minor role in SFI under the conditions employed here.

Strong field ionization with orbital angular momentum light beams measured with three-dimensional velocity imaging technique

256th National Meeting (2018)

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