Intended institutions and users:
Physics education in Medicine
In 1948 – before the era of lasers - Denis Gabor developed the transmission holography technique and took the first real holograms. For the invention of holography Gabor received the Nobel Prize in 1971. In 1962 Yury Nikolayevich Denisyuk developed a holography technique which allowed to observe holograms by means of white light source rather than a monochromatic one, defined as reflection holography. Although holography did not reach the expected practical breakthrough, it is still worth to pay attention to this fascinating technique.
The experimental set-up comprises a highly coherent green laser light source and the necessary optical components to create the expanded reference and object beam. With a few further components a Michelson interferometer is formed. The imaged interference pattern is used to check if the environment is free from vibration and other disturbances. Since a green laser source is utilised, appropriate film plates and developer are provided. Besides the optical components all required tools and materials are provided to make the developer and bleaching liquids out of provided dry chemicals. For the development of the exposed film plates all paraphernalia are provided.
The green emission of the an actively stabilized single mode laser is fed via a fibre collimator into the pig tailed fibre beam splitter creating two beams with same intensity. Each beam is guided in a single mode fibre to preserve the phase and coherence. One of the beams is directed to the object and the other to the film plate as reference beam. This unique arrangement of using modern fibre technology reduces significantly the extensive alignment of classical setup with spatial filter, separate beam splitter, expansion lens and beam bending mirrors. The optical fibre serves simultaneously as spatial filter, beam splitter and expansion lens. The only remaining adjustment is to direct the green laser radiation into the fibre, whereby the fibre collimator acts as a kind of a funnel. The precise 4 axes adjustment fine pitch screws provide a smooth and repetitious accuracy for an easy alignment process. The fibres coming from the beam splitter are terminated with ST fibre connectors and are connected to adjustment holder for precise and sustainable alignment to either the object or the film plate. This arrangement allows the convenient direction of the light beams without affecting the initial alignment and is not restricted to a mechanical structure. Thus all kind of holography types and object illumination can freely arranged.