Optical holography is a distinct imaging type where the end result is often referred to simply as a hologram. With this type of imaging, light is recorded according to its exact amplitude, as well as how it is reflecting off of the object that has been photographed. In optical holography, the completed result is represented as a three-dimensional (3D) image.
Holographic images are often used in science research, museum displays and various teaching environments. Researchers have also considered its use in x-ray technology. In addition to its more practical uses, optical holography is also often used in entertainment venues, such as stage presentations, community fairs and amusement parks. As this imaging science began to develop in the late 1940s and reached near-perfection in the 1960s, holograms can now be created for a variety of different uses. Such uses include small holographic images or seals used to enhance document security, images used in design presentations, holographic recreations used in science and technology, and three-dimensional images that are used solely for entertainment purposes.
In creating optical holography, it is necessary to split laser light in such a way so as to form two separate light beams. Using special equipment and film, one beam is used to shed light on the object while the second beam is used to reference the object. When the two are reintegrated, a hologram is formed and appears as a three-dimensional image.
Since its creation in 1948 by Dennis Gabor, holography has given birth to a variety of different types of holographic imaging. It is even responsible for a non-optical type known acoustical holography, which involves recording and reconstructing sound waves. All types of holography rely on the use of the interferogram, which is a deliberate interference of light waves that produce light and dark patterns as they are separated.
While optical holography has significant scientific, teaching and entertaining uses, researchers continue to explore its practical applications. One such use includes using optical holography techniques to detect flaws in objects and surfaces. For instance, deformities and other flaws in defense structures, such as airplanes, rockets and submarines, may not be visible to the naked eye. Using optical holography, however, engineers are able to locate damaged instruments and parts. Increasingly, it is also being used in the commercial aerospace industry for the purpose of inspecting aircraft vehicles to determine if unseen cracks and other damage is present on any part of the aircraft.