Transmission
hologram is a master or copy hologram in which the image can be viewed
when a light source passes through the recording medium, somewhat like a
slide. When a transmission hologram is a master hologram, it is
reconstructed using laser light. Copy transmission holograms, however,
are illuminated with white light, and in some cases, can be viewed with
a mercury or a sodium lamp.
Transmission holograms are lit from behind, bending the light as it
passes through the hologram to the eyes producing a virtual image. An
other characteristic of transmission holograms is that the object beam
and the reference beam come in from the same side of the holographic
film plate during the exposure.
When the developed film is illuminated, diffraction and interference
gives rise to a new wavefront quite similar to the original wavefront.
The result is that, it is difficult to see the difference between the
object and the image. The image appears to us as though it is formed at
a distance behind the filmplate. The plane of the image is called the
holographic window. This image is the virtual image.
Types of Transmission Hologram
- Laser Transmission Holograms - These are made
with lasers and also lit with lasers. The image produced appear in
the color of the laser used in illuminating them for viewing.
- White light transmission holograms - These are
illuminated with incandescent light or white light and produce
images that contain the rainbow spectrum of colors. The color
changes as the viewer moves up and down.
Transmission Holograms can also be classified as:
- A single beam transmission hologram is a very simple optical
arrangement and requires less system stability. This hologram is
called a transmission hologram because during the viewing of the
hologram the light source is on the opposite side of the hologram
from the viewer and the reconstructing light is "transmitted"
through the hologram.
- A multi beam transmission hologram create two or more beams with
a beamsplitter. The design helps to control the placement and
illumination of the object scene separately from the reference beam
and provides the proper placement of the real image for use in
making a white light reflection display hologram.
Applications of Transmission Hologram
- For security ID and labelling
- Commercial display
- On packaging
- For identification purpose
- For printing jobs
- Food and drug packaging
- Brouchers and catalogs
Post Your Purchase / Sourcing Requirements