  We present a study of collective multi-photon blockade in coherently driven
atoms in a single mode cavity. Considering two atoms strongly coupled to an
optical cavity, we show that the two-photon blockade with two-photon
anti-bunching, and the three-photon blockade with three-photon anti-bunching
can be observed simultaneously. The three-photon blockade probes both dressed
states in the two photon and three photon spaces. The two photon and three
photon blockades strongly depend on the location of two atoms in the strong
coupling regime. The asymmetry in the atom-cavity coupling constants opens new
pathways for multiphoton blockade which is also shown to be sensitive to the
atomic decay and pumping strengths. The work presented here predicts many new
quantum statistical features due to the collective behavior of atoms and can be
useful to generate non-classical photon pairs.
