ABSTRACT
This chapter reviews some general concepts about holography and discusses the recording of holograms on an electronic device and the digital reconstruction by using a computer. It presents some arrangements and their applications for the investigation of microscopic samples, shape contouring, and measurement of deformations. In classical holography, the interferences between reference and object waves are stored on high-resolution photographic emulsions, occasionally on photo-thermo plastic or photorefractive material. Classical and digital holograms may be classified according to the geometry used for the recording. Digital holography has been proposed for several applications, and the chapter reports few results showing that it can be used for the investigations of microscopical samples, for shape contouring and for the measurement of displacements. Digital holography has been extensively used for the measurement of deformations of large and microscopic objects, vibrations analysis, defect recognition, contouring, particle size and position measurements, and for the investigation of the change of refraction index of liquids and gases.
