What is Holographic Interferometry?

Holographic interferometry is a non-destructive and highly precise technique used in the field of optical metrology, in which an optical hologram is made of a subject, and the changes occurring on the subject are recorded and measured over time. It is used to measure the deformations or changes occurring in objects under different conditions, including mechanical, thermal, or electrical. The technique is based on the principle of interference of light waves and allows the user to measure distortions or changes on the surface or interior of objects, often in real-time.

Applications of Holographic Interferometry

Holographic interferometry is used in various industries, including aerospace, automotive, and electronics, to measure the structural integrity of objects under different conditions. It is used to measure the deformation of an aircraft wing under different loads, the thermal expansion of a turbine blade or automotive engine, or the deformation of electronic components due to changes in temperature. It is also used to measure the vibration modes of a structure, which helps in the design and optimization of structures.

How Holographic Interferometry Works

In holographic interferometry, a laser beam is split into two parts, a reference beam and an object beam. The object beam is directed towards the object, and the light scattered from the object is combined with the reference beam, creating interference fringes. A hologram is created by recording the patterns of these fringes on a holographic film. When the object is subjected to changes, the interference patterns on the holographic film also change, and these changes are measured using a readout system. The changes in the interference fringes are proportional to the changes in the object’s surface or interior.

Example: Holographic Interferometry in Industry

One example of the application of holographic interferometry in industry is in the aerospace industry, where it is used to measure the deformations of aircraft wings under different loads. Holograms are made of the wings under different loads, and the changes in the interference fringes are measured using a readout system. This data is then used to optimize the design of aircraft wings and ensure their structural integrity under various conditions. Holographic interferometry is also used in the automotive industry to measure the deformation of engine components due to thermal expansion, which helps in the design and optimization of engines.