Transverse Spin Angular Momentum of Airy Beams

We show that a (1+1)D Airy beam can contain the density of spin angular momentum (SAM) normal to the direction of propagation if the polarization direction of its magnetic-field component is orthogonal to the transverse axis of the Airy profile. Although the total SAM of the Airy beam is equal to zero, its main lobe (or main intensity peak) can contain a nonvanishing SAM. The transversal asymmetry inherent in the Airy beam, which results in its acceleration during propagation, determines the overall direction of this nonvanishing SAM.