  We report an experimental observation of quantum Airy disk diffraction
pattern using an entangled two-photon source. In contrast to the previous
quantum lithography experiments where the subwavelength diffraction patterns
were observed in the far field limit, we perform the Fraunhofer diffraction
experiment with a convex lens. The experimental result shows that the
two-photon Airy disk is provided with the super-resolution spot, which
surpasses the classical diffraction limit. In particular, the spot size can be
well controlled by the focal length, which adapted to optical super-focusing.
Our experiment can promote potential application of quantum lithography.
