  With exotic propagation properties, optical Airy beams have been well studied
for innovative applications in communications, biomedical imaging,
micromachining, and so on. Here we extend those studies to the quantum domain,
creating quantum correlated photons in finite-energy Airy transverse modes via
spontaneous parametric down conversion and sub-sequential spatial light
modulation. Through two-photon coincidence measurements, we verify their Airy
spatial wavefunctions, propagation along a parabolic trajectory, and that the
spatial modulation does not introduce any observable degradation of quantum
correlation between the photons. These results suggest the feasibility of using
spatially structured photons for practically advantageous quantum applications.
