When a volume holographic grating is readout under off-Bragg condition, determining the direction of the diffracted beam is an important issue in the coupled-wave theory of volume gratings.
体全息光栅的读出偏离布拉格条件时，衍射光方向的确定是体光栅耦合波理论中的一个重要问题。
2
Diffraction efficiency of volume Bragg grating, whose period is in the same order as the incident wavelength, is related to the polarization direction of the incident linear polarized beam.