Phy i unit v ppt holography
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Holography is a technique that uses the interference of light waves to record three-dimensional images. It involves splitting a laser beam into an object beam and a reference beam, with the object beam reflected from the object onto a photographic plate, where it interferes with the reference beam to create an interference pattern encoding the image. During reconstruction, an image can be retrieved by illuminating the hologram with light identical to the reference beam. Current applications of holography include security devices, medical imaging, and optical storage, while future uses may involve holographic televisions, night vision goggles, and computers utilizing holographic memory.
Phy i unit v ppt holography
- 1. Engineering Physics I Unit v Holography Presentation By Dr.A.K.Mishra Professor Jahangirabad Institute of Technology, Barabanki Email: akmishra.phy@gmail.com Arun.Kumar@jit.edu.in 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 1
- 2. Holography Whole + Writing + Drawing • Invented by Hungarian Physicist Danis Gabbor holography is a two step process. First step is recording of hologram where the object is transformed into image and letter reconstruction. • A hologram is result of interference occurring between two waves. • An object beam which scattered off. The object and coherent background and the reference beam which is directly reaching the photographic plate. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 2
- 3. Recording of Holograms • In this process the beam is divided into two beams, namely a reference beam and an object beam by beam splitter. The reference beam goes directly to the photographic plate and the second beam of light is directed into the object to be photographed. Each point of object scatters the incident light and acts as a source of spherical waves. Part of the light, scattered by the object, travels towards the photographic plate. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 3
- 4. • Process is as follows; • At the photographic plate the illuminated spherical waves from the object combine with the reference beam. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 4
- 5. • The sets of light waves are coherent because they are from the same laser. They interfere and form interference fringes on the plane of the photographic plate. • These interference fringes are a series of Zone – plate like rings. But these rings are also supremeposed and making a complex pattern of lines a swirl.These development negative of these interference pattern is a holograms. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 5
- 6. Reconstruction of images • For reconstruction the image 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 6
- 7. • For reconstruction the image, the real image holograms are illustrated by a parallel beam of light from laser. Light passes straight through and fringes act as diffraction grating. Light is diffracted and diffracted rays form two images, a virtual image and a real image. The real image is formed in front of the hologram. Since the light ray pass through the point where the real image is formed, it can be photographed. The virtual image of the hologram is only for viewing. The fundamental difference b/w hologram and photograph is, • In a photograph the information stored in ordinary fashion and object relates to conjugate point 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 7
- 8. Holography – Current and Future Applications • Holography is a very useful tool in many areas, such as in commerce, scientific research, medicine, and industry. • Some current applications that use holographic technology are: • Holographic interferometry is used by researchers and industry designers to test and design many things, from tires and engines to prosthetic limbs and artificial bones and joints. • Supermarket and department store scanners use a holographic lens system that directs laser light onto the bar codes of the merchandise. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 8
- 9. • Medical doctors can use three-dimensional holographic CAT scans to make measurements without invasive surgery. This technique is also used in medical education. • Holograms are used in advertisements and consumer packaging of products to attract potential buyers. • Holograms have been used on covers of magazine publications. One of the most memorable Sports Illustrated covers was the December 23, 1992 issue featuring Michael Jordan. Holograms have also been used on sports trading cards. • The use of holograms on credit cards and debit cards provide added security to minimize counterfeiting. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 9
- 10. • Holography has been used to make archival recordings of valuable and/or fragile museum artifacts. • Sony Electronics uses holographic technology in their digital cameras. A holographic crystal is used to allow the camera to detect the edge of the subject and differentiate between it and the background. As a result, the camera is able to focus accurately in dark conditions. • Holography has been use by artists to create pulsed holographic portraits as well as other works of art. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 10
- 11. Future applications of holography include • Future colour liquid crystal displays (LCD’s) will be brighter and whiter as a result of holographic technology. Scientists at Polaroid Corp. have developed a holographic reflector that will reflect ambient light to produce a whiter background. • Holographic night vision goggles • Optical computers will be capable of delivering trillions of bits of information faster than the latest computers 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 11
- 12. • Many researchers believe that holographic televisions will become available within 10 years at a cost of approximately $5000. Holographic motion picture technology has been previously attempted and was successful in the 1970s. The future of holographic motion pictures may become a reality within the next few years. • Holographic memory is a new optical storage method that can store 1 terabyte (= 1000 GB) of data in a crystal approximately the size of a sugar cube. In comparison, current methods of storage include CD’s that hold 650 to 700 MB, DVD’s that store 4.7 GB, and computer hard drives that hold up to 120 GB. 6/24/2017 Dr A K Mishra, Academic Coordinator, JIT Jahangirabad 12