Nanoscale quantum optics shows great promise as a platform for future quantum information applications, owing to its compact dimensions, enhanced light-matter interactions, and compatibility with current on-chip technologies. In such nanoplatforms, single photons can carry quantum information in various physical degrees of freedoms such as position, propagation direction, time slot, frequency, energy, orbital angular momentum, and spin. In macroscopic settings, the spin and orbital angular momentum of light are separable, hence can be utilized as separate degrees of freedom present entanglement between them [1]. But in nanophotonic platforms the electromagnetic waves are strongly confined, hence the spin and orbital angular momentum of light become inseparable, leaving only the total angular momentum of the confined modes as a good quantum number.
This talk will present our studies on photons entangled in their total angular momentum in a nanophotonic platform [2], where the spin and orbital angular momentum of light are inseparable. On the fundamental side, we unravel the evolution of quantum information in heralded single photons as they couple into- and out of- the near-field of a nanophotonic system. We find that the qubit encoded in total angular momentum of the near-field photons becomes a free-space qudit entangled in the photonic spin and orbital angular momentum degrees of freedom. Finally, the talk will touch upon some of our newer projects, dealing with encoding quantum information in quantum skyrmions [3] and plasmonic lattices which expand the Hilbert space into hyper-entangled states [4].
[1] Stav, Tomer, et al. "Quantum entanglement of the spin and orbital angular momentum of photons using metamaterials." Science 361.6407 (2018): 1101-1104.
[2] Kam, Amit, et al. "Near-field photon entanglement in total angular momentum." Nature 640.8059 (2025): 634-640.
[3] Kam, Amit, et al. "Quantum skyrmions and high dimensional entanglement mediated by nanophotonics." To appear in eLight. https://doi.org/10.1186/s43593-026-00124-1
[4] Fridman, Lior, et al. "Hyperentanglement in Nanophotonic Systems with Discrete Rotational Symmetry." arXiv preprint arXiv:2511.00860 (2025). To appear in Nanophotonics.
Speaker's Bio
Amit Kam is a Ph.D. student in Physics at the Technion - Israel Institute of Technology, where he conducts research on quantum nanophotonics and structured light under the supervision of Prof. Guy Bartal. He holds both a B.Sc. and an M.Sc. in Physics from the Technion.