  We present a study of the electromagnetic control of nonclassicality of the
outgoing light field in a single atom cavity QED system. By exploring the
energy eigenvalues and eigenstates, we show that the eigenstates are similar to
the Jaynes-Cummings ladder of eigenstates and can be optically controlled by an
external control field. Tuning the control field frequency to the one photon
resonance, we show the superbunching behavior in the outgoing light field can
be observed at the frequency of one photon resonance. We also show that there
exists a magic control field intensity at which two photon blockade phenomenon
can be significantly improved. In particular, it is possible to adjust the
nonclassicality of the outgoing field from quantum to classical by varying the
control field intensity. The work presented here provides an optical method to
control statistical features of the outgoing field and can be useful for the
nonclassical light generation, quantum gate operation and exotic quantum state
generation.
