A holographic image is a pattern of light waves created by a coherent beam of light from a laser, and recorded on a screen, film, or photographic plate. This kind of imaging requires a laser beam that is split into two parts as it reaches the surface of an object. The reference beam records an image directly onto a photographic plate of film surface, while the second beam provides a reflection of the object, recording an image of the object. Both parts of the split beam have traveled different paths, are no longer coherent, and thus, create a light interference pattern which when illuminated by the same type of coherent laser light, creates a three-dimensional image of the object. The actual scientific technique used to create holographic imaging is known as wave front reconstruction.
Like most scientific discoveries, the concept of holography, or electron holography was discovered accidentally by the Hungarian-born British physicist Dennis Gabor as he was conducting research regarding improvements to the electron microscope. Electron holography as it was originally discovered is still used in the field of electron microscopy. The modern version of the hologram, as people understand it in the early 21st century, was not developed until 1960, when laser technology could make a light-opitcal image visible. The first practical three-dimensional versions of a hologram were created in 1962 in the Soviet Union by Yuri Denisyuk.
There are several different types of holograms. For transmission holographic imaging, the type usually depicted in science fiction movies, a monochromatic light source passes through the hologram to create a visible image. Reflection holographic imaging produces the kind of holograms seen on credit cards and DVD stickers. White light is reflected off the surface of a hologram to create a visible image. The brain perceives the light shining through or reflecting off a hologram and interprets the resulting light pattern as a three-dimensional image.
As of 2011, a type of holographic imaging is being developed and used by some high-tech companies called holographic telepresence. In this new holographic imaging technology, a mixture of voice and video are transmitted over an Internet connection and combined to recreate a real-time, life-sized hologram of the person speaking from a remote location. Doctors are currently using this holographic imaging technology to transmit a life-sized holographic image in order to examine patients, or rather, their holographic image, and conduct a real-time diagnosis. Justice systems and courts around the world are also looking to implement this new holographic imaging technology to bring court systems to rural areas where no court system yet exists. Through holographic imaging technology, the meetings, boardrooms, and courtrooms of the future will allow all parties to appear together in the same room even if they are not physically present.