The use of structured light as a quantum resource requires the ability to construct the density matrix of spin-orbit states from measurements. In this paper, we propose and experimentally demonstrate the tomography for a wide class of spin-orbit modes, including mixed modes. By combining polarimetry and image analysis of the transverse modes, we can obtain the density matrix of the corresponding quantum state with high fidelity. Informational completeness of the method is achieved through the analysis of the direct and astigmatic images of the spatial modes exiting each port of the polarimetric measurement. The required astigmatism is produced by a spherical lens suitably tilted with respect to the beam's propagation direction. This operation lifts the image degeneracy of modes carrying opposite orbital angular momenta and completes the information about the density matrix.

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• Lenses
• Optical sources & detectors
• Imaging & optical processing
• Optical techniques