Lasers and Holograms

1. Lasers and Holograms

2. What does LASER stand for? LASER is short for Light Amplification by Stimulated Emission of Radiation Lasers are constantly around us DVDs, laser shows, medical (laser surgery), laser sight.

3. Properties of lasers • Laser light is DIRECTIONAL • Is strong and concentrated • Flashlights are much weaker. • the light is COHERENT • Each wavelength is in unison with the others...think of the British (laser light) vs. Minutemen (flashlight) • The laser lights are all organzied and together. • The flashlights are running all over the place...unorganzied

4. Origins • Theodore Maiman invented the first laser in 1960. (ruby laser) • The idea of stimulated emission was theorized first by the non-other Albert Einstein.

5. Organized (laser) Random (flashlight)

6. How do lasers work? A laser is activated by a few photons. These active photons cause more and more photons to get “excited” and thus creating a laser beam. Laser beams are usually the same color as opposed to light.

7. Laser TV technology • When you watch an average tv today, you can only see 30-35% of the ACTUAL color content • New developments in laser technology will allow you to see 90% of color content! • Cheaper as well.

8. Military Lasers Laser weapons are just now reaching the battlefield. Researchers at the pentagon recently got 105KW of power out of their laser. This paves the way for energy weapons to be the newest destructive force on the battlefield.

9. LASER TAG!!!!!!! Uses coded lasers to track how many points you get.

10. Holograms • Holography, a term used to describe the study of holograms, is is a technique that allows the light scattered from an object to be recorded and later reconstructed so that it appears as if the object is in the same place where it was recorded. • The image produced is changed exactly as the postion of the viewing system changes, thus producing a three dimensional image.

11. History of Holograms • Holograms were first discovered by a physicist named Dennis Gabor. He came upon the hologram as he was searching for ways to improve the electron microscope. • In 1962, the first optical hologram was created at the University of Michigan by Emmett Leith and JurisUpatneiks. • They created several types of holograms. The first and most simple hologram they created was called a transmission hologram which used lasers to record the object. The second type of hologram was called therainbow transmission hologram. These are most commonly seen on objects such as credit cards.

12. Interference and Diffraction Holographic reconstruction process • A photographic plate (metal plate with slits in it) is placed at an angle to the 3-D object being hologramed. • The laser beams that are shot toward the object are bent and reflected toward the photographic plate. • The angles at which the lasers hit the photographic plate deterimine the shape of the object to be hologramed later.

13. Holograms of Complex Objects • To record a complex object, the laser beam is first split into two beams using a beam splitter. • One of the beams illuminates the object (reflecting the object onto the recording medium), while the other beam illuminates the recording medium directly.