geologia: Physics of optical holography

Evidence: 100 • authority: 72

Optical holography is a technique which enables an optical wavefront to be recorded and later re-constructed. Holography is best known as a method of generating three-dimensional images but it also has a wide range of other applications. A hologram is made by superimposing a second wavefront (normally called the reference beam) on the wavefront of interest, thereby generating an interference pattern which is recorded on a physical medium. When only the second wavefront illuminates the interference pattern, it is diffracted to recreate the original wavefront. Holograms can also be computer-generated by modelling the two wavefronts and adding them together digitally. The resulting digital ima…

Evidence: 83 • authority: 72

Holography is an imaging technique that allows a wavefront to be recorded and later reconstructed. It is best known as a method of generating three-dimensional images, and has a wide range of other uses, including data storage, microscopy, and interferometry. A hologram is a recording of an interference pattern that can reproduce a 3D light field using diffraction. In general usage, a hologram is a recording of any type of wavefront in the form of an interference pattern. It can be created by capturing light from a real scene, or it can be generated by a computer, in which case it is known as a computer-generated hologram, which can show virtual objects or scenes. Optical holography needs a…

Evidence: 48 • authority: 72

Computer-generated holography (CGH) is a technique that uses computer algorithms to generate holograms. It involves generating holographic interference patterns. A computer-generated hologram can be displayed on a dynamic holographic display, or it can be printed onto a mask or film using lithography. When a hologram is printed onto a mask or film, it is then illuminated by a coherent light source to display the holographic images. The term "computer-generated holography" has become used to denote the whole process chain of synthetically preparing holographic light wavefronts suitable for observation. If holographic data of existing objects is generated optically and recorded and processed…

Evidence: 42 • authority: 88

Vectorial wavefront holography based on a polarisation-insensitive hologram. Abstract Polarisation holography generally demands polarisation-sensitive holograms for reconstructing either polarisation-multiplexed holographic images or polarisation-sensitive image channels. To date, polarisation holography is underpinned by the Jones matrix method that uses birefringent holograms, including ultrathin metasurface holograms, limiting the polarisation control to orthogonal polarisation states. Here I introduce a novel concept of vectorial wavefront holography by exploiting the wavefront shaping of a structured vector beam. I will show that a phase hologram can be used to tailor the polarisation…

Evidence: 42 • authority: 72

Holographic interferometry (HI) is a technique that enables the measurement of static and dynamic displacements of objects with optically rough surfaces at optical interferometric precision (i.e., to fractions of a wavelength of light). These measurements can be applied to stress, strain, and vibration analysis, as well as to non-destructive testing and radiation dosimetry. It can also be used to detect optical path length variations in transparent media, which enables, for example, fluid flow to be visualized and analyzed. It can also be used to generate contours representing the form of the surface. Holography is the two-step process of recording a diffracted light field scattered from an…