The data encoder (e.g. an amplitude spatial light modulator, ASLM) in a volume holographic storage system is rotated by 45.degree. relative to the normal to the plane of the reference and signal beams, such that the near-Fourier transform pattern of the encoder at the medium has an X-shape. The encoder rotation allows tight packing of spatial multiplexing subvolumes in a rectangular array, and provides for uniform spatial frequency filtering in a perpendicular geometry.