Analogue Holograms
Analogue master holograms is one of the most accurate ways in which to record real life objects.
Display holograms of the analogue type are the ones most often used for advertising and exhibitions. These holograms are recorded with either continues wave (CW) lasers or pulse lasers, the technique, where by an intense flash of laser light is emitted with a very short duration and high peak power.
To generate the master hologram which is of the transmission type, the laser beam is diverted to generate a reference beam and an object beam. The reference beam often bounced off a high grade front surface mirror.
The object beam illuminates the subject through a ground glass in a safe way which makes it possible to safely record the eyes. Even if the process takes place at millionths of a second it is some of the most beautiful light you will ever see.
The final hologram (hologram copy) is recorded using the master plate to produce a hologram where the image often is focused within the copy plate (part of the image is in front of the plate and part behind). This hologram is generally of the reflection type to make it possible to use white light to view the final plate.
If more than one master hologram is used when generating the final reflection hologram it is possible to store two images in the same plate. When you walk from left to right in front of the hologram, one image turns into the second one.
Another reflection type of hologram is the single-beam Denisyuk hologram which is most suitable for recording and archiving museum artefacts. This type has a 180-degree field of view, which make the images very realistic looking. The early ones were made with only one laser wavelength which produced only monochrome 3-D images.
The latest development is the introduction of colour holograms which make them more accurate to the real object, this is particular important for museums and exhibitions. This is one area of holography that View Holographics specialise in and are set up for recording museum artefacts.
