Abstract: Some embodiments are directed to a system for measuring vibrations of a surface of a mechanical part, by digital holography. The system includes a source of radiation emitting in a predetermined range of frequencies, a first separator element configured to define a first incident ray and a reference ray, a module for shaping a second incident ray from the first incident ray, and an optical element configured to make the reference ray and a radiation produced by a reflection of the incident ray on the surface of the mechanical part interfere. The module for shaping the second incident ray includes diffracting optical elements having a diffraction structure to diffract the incident radiation. The structure is from a polymer, sol-gel or photoresin material resting against a glass substrate, the structure including elements etched in a plane parallel and/or orthogonal to the substrate, with dimensions from 100 nanometres to 100 micrometres.

Abstract: A system for measuring vibrations of a surface (VSURF) of a mechanical part (M), comprising a source (SOURCE) of radiation (L), a first separator element (ELI) configured to define a first incident ray (LB1) and a reference ray (RLB), a shaping module (DOEM) producing a second incident ray (LB2) from said first incident ray (LB1), and an optical element (OE) capable of an interferential addition of the reference ray (RLB) and a ray produced by a reflection of said second incident ray (LB2) on said surface (VSURF), the shaping module (DOEM) comprising one or more diffracting optical elements (DOE1, . . . , DOEn), each comprising at least one diffraction structure (FSTRUCT) diffracting all or part of the first incident ray (LB1) so as to illuminate a chosen surface of the mechanical part.