[en] Results are described on the observation of isolated single photons by the DO detector at the Fermilab anti pp collider. The inclusive cross section has been measured for photons in the central rapidity region (| η |< 0.9) above 10 GeV E_T. Studies of jets recoiling against the single photon permit the measurement of the fundamental hard scattering cosθ* distribution. An analysis of the η correlations between high-E_T photons and the leading jet probes the gluon x distribution. Diphoton production measurements are used both as a test of QCD processes and as a search for resonant structure, including bosonic Higgs production