Figure 3.
(a) As the coherence length of the neutron wavepackets is much smaller than the beam diameter, we may differentiate between ‘extrinsic OAM’ calculated w.r.t. the SPP axis as the cross product of wavepacket’s position and its total linear momentum, and ‘intrinsic OAM’ which is associated with helical wavefronts [42, 43]. The black arrows on top of the wavepackets indicate the direction of the induced diffraction due to the SPP. (b) The probabilities of the n = 0, 1 and ℓ = 0, 1 states when a neutron wavepacket with no OAM nin = ℓin = 0 passes through an SPP with q = 1. The probabilities are calculated w.r.t. the neutron’s propagation axis and they are plotted as a function of the rescaled distance from the center of the SPP, ρ0/σ⊥, where ρ0 is the distance between the SPP axis and the wavepacket’s propagation axis, and σ⊥ is the transverse coherence length of the wavepacket.