Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 52: Structured Light

Q 52.1: Invited Talk

Thursday, March 14, 2024, 14:30–15:00, HS 1221

Structured light and its interaction with matter — •Robert Fickler, Rafael Barros, Lea Kopf, and Marco Ornigotti — Tampere University, Tampere, Finland

Shaping light fields in all degrees of freedom, i.e., space, time, and polarization, has become a versatile tool to explore fundamental optics effects and fruitful applications in various fields of photonics and quantum optics. In this talk, I will present some of our recent studies in this thriving branch of optics.

At first, I will discuss the behavior of light having optical phase vortices getting reflected off a planar surface. It was predicted that higher-order vortices split into a constellation of unit-charged vortices, a phenomenon which is related to fundamental optical beam shifts. We were able to observe this effect for the first time experimentally and proof that that the physical quantity of interest is the mathematical abstraction of elementary symmetric polynomials of the coordinates of a vortex constellation. Our results pave the path to novel material characterization techniques and might also find applications in other system exhibiting vortices, e.g., superfluids or Bose-Einstein condensates.

I will then present a simple experimental scheme to generate more complex states of light in which space, wavelength, and polarization are non-separable. We demonstrate that these so-called spatio-spectral vector beams can exhibit simultaneously all possible polarization states across their frequency spectrum and transverse spatial extent and point out interesting analogies to entangled tri-partite quantum systems.

Keywords: twisted light; optical vortex; optical beam shifts; structured photons