General English


  • noun a three-dimensional picture which is used on credit cards as a means of preventing forgery


  • noun an imaginary three-dimensional image produced by the interference pattern when a part of a coherent light source, e.g. a laser, is reflected from an object and mixed with the main beam


  • A three-dimensional image which is recorded on a suitable medium such as a high resolution photographic plate. The recording medium stores an interference pattern which is formed by a coherent beam of light reflected by a reference mirror, and by light scattered by the object being photographed. A laser usually serves as the source of the coherent light. When suitably illuminated, it produces a three-dimensional image in space. A hologram may be incorporated into a credit card, for instance, as a measure to help prevent fraud. acoustic or radio waves may also be utilized to create a hologram.


  • noun a three-dimensional photographic image created by laser beams