seminar topic of holography.ppt
- 1. Word Origin Hologram is from the Greek word holos, meaning whole and gramma meaning message.
- 2. Hologram History Theory Developed in 1947 by British/Hungarian scientist Dennis Gabor Developed because he was trying to improve the resolution of electron microscopes Development in this field was stifled during the 1950’s because light sources were not coherent
- 3. History Continued In 1962 Emmett Leith and Juris Upatnieks realized that holography could be used as a 3-D visual medium From their work, they used a laser to create the first hologram in history, that of a toy train and bird This type of hologram required laser light to be viewed, though.
- 4. What is Holographic Memory ? • It is a memory that can store information in form of holographic image. • It is a technique that can store information at high density inside crystals or photopolymers. • It provides data to be written beneath the surface of the disc. • Holographic memory can store up to 1 Tb in a storage medium the size of a sugar cube crystal.
- 5. White Light and High Speed Objects In 1962 Dr. Uri Denisyuk of the former U.S.S.R. developed a white light reflection hologram, which could be viewed in light from a normal incandescent bulb. In 1960, with the invention of the pulsed-ruby laser, holograms of high speed objects was made possible
- 6. Pulsed-Laser Holography Laser system emits a very powerful burst of light that lasts only a few nanoseconds, which effectively freezes movement Enables a hologram to be made of a human The first hologram of a person was made in 1967
- 8. Dr. Dennis Gabor 18” x 24” portrait Recorded in 1971 Paved the way for pulsed holographic portraiture Portrait commemorated Gabor winning the Nobel Prize that year
- 9. Dr. Stephen A. Benton Dr. Stephen A. Benton invented white-light transmission holography in 1968. This type of hologram can be viewed in ordinary white light creating a rainbow image from the seven colors making up white light. His work made possible the mass production of holograms using an embossing technique.
- 10. How Holograms are Made Need a laser, lenses, mirror, photographic film, and an object The laser light is separated into two beams, reference beam and object beam Reference beam enlarged and aimed at a piece of holographic film
- 11. Making Holograms Object beam directed at subject to be recorded and expanded to illuminate subject Object beam reflects off of object and meets reference beam at film Produces interference pattern which is recorded
- 12. Making Holograms Cont. Film is developed Hologram illuminated at same angle as reference beam during original exposure to reveal holographic image
- 13. Continues..
- 16. Properties of Hologram • A block or sheet of photosensitive material which records the diffraction of two light sources. • A laser beam is splatted into two beams: Source beam Reference beam • The two beams diffracts to form the image on the recording medium
- 17. Physical Concepts Lloyd’s Mirror Reflection Light Wave Interference and Diffraction
- 18. Applications of Holography Design of containers to hold nuclear materials Credit cards carry monetary value Supermarket scanners Optical Computers Improve design of aircraft wings and turbine blades Used in aircraft “heads-up display” Art Archival Recording of fragile museum artifacts
- 19. Holography in the Future Medical Purposes Gaming Systems Personal Defense Computers Artwork Amusement Park Rides
- 20. Conclusion • Built on technology that’s around for 40+ years • Holographic Memory is the future of data storage o HUGE capacity, Very fast, Smaller o Parallel processing • Current storage methods nearing there fundamental limits of storage density • Large market and little new competition