Manipulation and reconstruction of structured light

In quantum information, the capability to control and manipulate high dimensional quantum states is of crucial interest. We experimentally demonstrate an engineering protocol based on the Quantum Walk dynamic encoding the walker state in the orbital angular momentum (OAM) degree of freedom and the coin state in the polarization. In each step, the coin state is controlled by a set of wave plates and the walker state by a device (q-plate) that can conditionally change the OAM according to the polarization [1]. Moreover, we characterized structured beams characterized by a not uniform distribution of the polarization on the transverse plane (Vector Vortex Beam), by using machine learning techniques. In particular, we obtained optimal results using both Convolutional Neural Network and Support Vector Machine supported by Principal Component Analysis (PCA). Furthermore, relevant input states are reconstructed through the PCA technique [2].

[1] T. Giordani, E. Polino, S. Emiliani, A. Suprano, L. Innocenti, H. Majury, L. Marrucci, M. Paternostro, A. Ferraro, N. Spagnolo, and F. Sciarrino. Phys. Rev. Lett., 122:020503, 2019.
[2] T. Giordani, A. Suprano, E. Polino, F. Acanfora, L. Innocenti, A. Ferraro, M. Paternostro, N. Spagnolo, and F. Sciarrino. Phys. Rev. Lett., 124:160401, 2020.