We detailed the generation of GeV-photon beams with the polarization degree exceeding 90% and with a brilliance of the order of 10²¹ photons/(s mm2 mrad2 0.1% BW) using currently available multi-GeV electron bunches and laser pulses of moderately relativistic intensities. The polarization of photon beams could be finely controlled by the laser polarization, and for 10-GeV electron bunches, the photon beam's brilliance is maximized in the moderately relativistic intensity region. We demonstrate the robustness of this scheme by considering electron bunches of various emissivities colliding with linearly and circularly-polarized laser pulses at a range of angles.

nonlinear Compton scattering,polarized gamma photon,strong field qed