Measurement of phase invariants in three-beam diffraction

Abstract

The method of determining phase invariants in three-beam diffraction introduced by Bird et al. [Phys. Rev. Letters 59 (1987) 1216] is analysed. The applicability of their perturbation expansion is discussed, along with the effects of higher-order terms on the prescription for phase measurement. It is shown that the method can provide accurate phase invariants in experimentally realisable conditions.