Optics

• Holography is the branch of optics that makes a hologram possible. The coherent laser light preserves the 3-D information of a holographic image with the source of a white light.
  
  

Uses

• Holographic images are commonly used in amusement parks for entertainment, as well as security applications and art installations. Leading technology aircraft and automobile companies can also use holograms in presentations.
  
  

Types

• There are various types of holograms. Silver halide film, which is similar to camera film, is the oldest kind that is used commonly for wall images. A dichromate hologram is used in jewelry, such as holographic watches, and is made of gelatin.
  
  

Techniques

• There are different techniques used to make holographic images. A subject of a single-image hologram sits still and looks 3-D while a multi-channel hologram accomplishes the illusion of the image moving by alternating between two or three channels of the same image in different angles.
  
  

Fun Fact

• A "holograph" is also used to describe a document handwritten by the author or the handwriting itself.