Crystallographic heterodyne phase detection for highly sensitive lattice-distortion measurements

Noting the structural similarity between a distorted lattice in a crystal and a spatially phase-modulated fringe pattern in optical metrology, we propose a crystallographic lattice heterodyne technique. The technique detects lattice distortions as spatial phase modulations, where the phase change by 2π corresponds to the displacement of atoms or lattice points by a distance equal to the lattice constant. By virtue of heterodyne detection, the technique has the potential for determining the lattice distortions to several hundredths of the lattice constant.