Prof. Shlomi Arnon

Structured light carrying Orbital Angular Momentum (OAM) enables high-dimensional photonic quantum information processing. In this work, we propose and theoretically demonstrate a four-dimensional controlled-NOT (CNOT) quantum gate implemented using the radial (p) and azimuthal (l) degrees of freedom of Laguerre–Gaussian modes. Quantum information is encoded within a single photon, with the radial mode acting as the control qubit and the OAM mode as the target qubit. The gate is realized using fully linear and unitary optical transformations based on Fourier transform based radial mode sorting and OAM inversion within the architecture. This approach enables deterministic two-qubit logic in an expanded Hilbert space, providing a scalable pathway toward high-dimensional quantum gates using structured light.