Hologram is a three – dimensional image formed by the interference of light beams from a laser or other coherent source. It is formed when a point source of light of fixed wavelength encounters light of the same fixed wavelength arriving from an object. When the hologram is illuminated by the reference beam alone, the diffraction pattern recreates the wave fronts of light from the original object. Thus, the viewer sees an image indistinguishable from the original object.
Holograms are mainly classified into two categories –
Reflection hologram – This type is more common in galleries. The hologram is illuminated by a white incandescent light, held at specific angle and distance and located on viewer’s side of hologram. Thus, the image consists of light reflected by the hologram.
Transmission hologram – A typical type of this hologram is viewed using laser light. The light is directed from behind the hologram and the image is transmitted to the observer’s side. The virtual image generated can be very sharp and deep. If these hologram is broken into small pieces still the entire scene can be seen through each piece.
Many variations can be made using these two types they are called hybrid holograms. Some types of hybrid holograms are Embossed holograms, integral hologram, multichannel holograms etc.
Uses of hologram –
Any company can use hologram to enhance the image of their brand as a genuine and authenticated brand. They can be used for fancy packaging, security applications. Few common uses are –
- Display of artefacts – Many museums have made article of hologram, both for insurance purpose and to check for deterioration.
- Security – The use of holograms in credit cards and bank notes reduces their chances of forgery.
- Display Holography – It uses pulsed lasers to capture the image of plants, animals and unanimated objects.
- Medical – Holography can be used for visualizing patient data. Many advanced image generating techniques like MRI and ultrasound scans generate complex data which normally generates flat image on scree but holography can be used to generate a 3-D image.
They can also be used for military mapping and information storage.
There is great deal of research going on this field. Applications are changing lives, saving lives and stimulating creative and intellectual discussion.
We know that future is bright – it might be holographic.