  The thermal-photon emission from strongly coupled gauge theories at finite
temperature via the bottom-up models in holographic QCD in the deconfined phase
is studied. The models are constructed to approximately reproduce the electric
conductivity obtained from lattice simulations for the quark gluon plasma
(QGP). The emission rates are then embedded in hydrodynamic simulations
combined with prompt photons and hadronic contributions to analyze the spectra
and anisotropic flow of direct photons in RHIC and LHC. In general, the
holographic models enhance the yield and improve the agreement in spectra,
while they reduce the flow in low $p_T$ and increase it in high $p_T$.
