<p>The physical mechanism of reconstruction and amplification of an object wave upon diffraction of a reference wave by a sinusoidal phase-absorption holographic grating formed in a cubic optically active photorefractive crystal was studied. The vector amplitude of the reconstructed wave was found in the framework of the proposed analytical approach as the resulting sum of oscillations of diffracted waves of variable amplitude emitted by thin layers of the holographic grating. The polarization condition under which the diffraction efficiency of the hologram and intensity transfer during two-wave mixing reached maximum values was formulated. The dependences of the output energy characteristics of the phase-absorption hologram on the crystal thickness calculated using the analytical approach were shown to agree with data obtained by solving coupled-waves equations.</p>