  We investigate the charged pion photoproduction off the proton target with
the Delta(1232) baryon in the final state, i.e. gamma p -> pi^- Delta^++(1232)
and gamma p -> pi^+ Delta^0(1232), based on the effective Lagrangian method,
beyond the resonance region, E_cm >~ GeV. We employ the pi- and rho-meson Regge
trajectories in the t-channel, in addition to the proton- and Delta-pole, in
the s- and u-channels respectively, and the contact-interaction contributions.
A specific scheme for the form factor which satisfies the Ward-Takahashi
identity, crossing symmetry, and on-shell condition, is taken into account. To
discuss the validity of the Regge approach within the Effective Lagrangian
method, we also consider a smooth interpolation between the Regge- and
Feynman-propagators for the t-channel meson exchanges as a function of sqrt(s).
We present the numerical results for the energy and angular dependences of the
cross sections, and double-polarization observable. It turns out that the
present framework shows the significance of the pi-exchange and contact
interaction terms to reproduce the experimental data qualitatively well.
Especially, the interpolation between the two propagators plays a crucial role
to reproduce the high-energy experimental data. The pi^+ decay-angle
distribution is also studied using the Delta^++ decay frame, i.e. the
Gottfried-Jackson frame. The present results will be a useful guide for future
high-energy photon-beam experiments.
