  We theoretically investigate the three-photon blockade phenomenon in a two
atoms cavity QED system, where two atoms are driven by a coherent field. In the
case of in-phase radiations, we show that the three-photon blockade with
bunched two photons can be realized in a small regime of the driving field Rabi
frequency. However, in the case of out-of-phase radiations, the one-photon
excitations are prohibited due to the destructive interference, and
three-photon blockade can be realized in a wide regime of driving field Rabi
frequency. In addition, the three-photon blockade phenomenon can be
significantly improved. The results presented here show that this two-atom
scheme is a good candidate to achieve anti-bunched photon pairs.
