Holograms?

1. A 3-D Hologram poster for the movie Terminator: Salvation What is the future of Holograms? Group Members: Abad, Anne Badruddin, Aamir Kahlon, Sarpreet Kang, Bhavneet Kuner, Amrit Mandalagiri, Mrinlini Ramdonee, Mohnish

2. Introduction to Holograms • Holograms, even though one might not be aware of it, are all around us • Don’t believe it? • If you don’t, then take out your driver’s license • See that image at the bottom right corner, that is a hologram • Now look at the image at different angles. Notice how you still see the same image from every angle , but from different perspective just like one would in reality…, that is the main characteristics of a hologram • This is only one example where one can find these holograms. Truth is, they can be found almost everywhere, from Game • These examples are of relatively simple holograms, mostly used to make forgery harder, are not very effective. Most of the time they are simply smears of colours or a sparkly picture than actual stunning 3D image. • This PowerPoint presentation has been made to explain how the holograms are made and reconstructed

3. How are they made? • There are different kinds of holograms that can be made. In this PowerPoint, we will focus on the two main types of holograms The two types are: • Transmission Holograms • Reflection Holograms

4. Transmission Holograms: Overview • These types of holograms differ from reflection holograms in the way they are created • Reflection holograms are created by reflecting a beam of light off of the surface of the object onto the photographic plate • But transmission holograms are created by transmitting a beam of light off of a mirror and a object onto the photographic plate

5. Transmission Holograms: Overview • Whilst reflection holograms do produce very high quality images, they are extremely expensive to create • On the other hand, transmission holograms are able to be mass produced at a much cheaper cost, with a slightly different method of creating it

6. Transmission Holograms: applications • Transmission holograms are commonly used for art and security purposes • The shiny images seen on credit cards, products, and currency bills in Canada utilize transmission holograms to ensure their authenticity • Holograms are extremely difficult to copy, so criminals will be unable to create counterfeit money • There are numerous other uses for transmission holograms, such as for holographic art and for covers of magazines or novels

7. Transmission Holograms: recordings • In the creation of transmission holograms, there are two steps; recording and reconstruction • To record an image onto a photographic plate, a powerful laser is needed, a beam splitter, two beam spreaders, the object itself, two mirrors, and the photographic plate

8. Transmission Holograms: recording This image shows the set up of creating a transmission hologram. The steps are detailed on the next slide.

9. Transmission Holograms: recording • The laser is used to provide a focused source of light, with uniform wavelengths • The beam of light is split into two after passing through the beam splitter, and is then spread out through the beam spreader • The object beam bounces off of the mirror, and then rebounds off of the object onto the photographic plate • The reference beam bounces off the mirror and bounces directly onto the photographic plate

10. Transmission Holograms: recording • The object and reference beam lights are each a wave, which create a resultant wave through superposition • The troughs and crests of the waves are added at each position, and the amplitude and phase of the wave is recorded onto the photographic plate as an interference pattern This image shows the final step of the recording process. The object beam and reference beam meet at the photographic plate to create a resultant wave with its own interference pattern.

11. Transmission Holograms: reconstruction • The next step in creating a transmission hologram is the reconstruction of the image • A reconstruction beam is shot at the same angel as the reference beam was during the previous step • When the angles are equal, three beams are produced on the other side of the hologram • These beams are the non diffracted beam, the secondary image beam, and the primary image beam

12. Transmission Holograms: reconstruction The secondary and primary image beams bend away from the non diffracted beam at the same angle . The angle between the two image beams is equal to twice that of , so 2. Depending on the angle at which we view the hologram, we will see different images. If we look at the same angle as the primary image (example; same angle as the object beam hit the photographic plate), we see the virtual image of the object behind the hologram.

13. Transmission Holograms: reconstruction Diagram showing First-order virtual image reconstruction Diagram showing First-order real image reconstruction However, if we look at the hologram at the same angle as the secondary image beam, we see the real image in front of the hologram.

14. Reflection Holograms: recording • A laser is shown through a beam splitter • This allows half the laser to go through while the other half is bounced towards the object • The beams next go through a beam spreader – a lens that spreads the laser • The object beam bounces off the object then hits the hologram (photographic plate) • The reference beam hits a mirror and directly hits the holograms • The photographic plate creates an interference pattern which records the information of the resultant waves

15. The recording of holograms • Light is made of high-frequency electrical and magnetic waves. These waves have peaks and troughs and can travel in a straight line until they encounter an obstacle. • Obstacles can absorb or reflect light. • The wavelength of light is the distance from one peak of the wave to the next. • This relates to the wave's frequency, or the number of waves that pass a point in a given period of time. • The frequency of light determines its color and is measured in cycles per second. • Colors at the red end of the spectrum have lower frequencies, while colors at the violet end of the spectrum have higher frequencies. • Light's amplitude, or the height of the waves, corresponds to its intensity.

16. The recording of holograms Cont... • The light-sensitive emulsion used to create holograms makes a record of the interference between the light waves in the reference and object beams. • When two wave peaks meet, they amplify each other. This is constructive interference. • When a peak meets a trough, they cancel one another out. This is destructive interference. • At every point at which the two beams intersect, these two numbers add up, either flattening or amplifying that portion of the wave. • The silver halide in the emulsion responds to these light waves just like it responds to light waves in an ordinary photograph. Parts of the emulsion that receive more intense light get darker, while those that receive less intense light stay a little lighter. • These darker and lighter areas become the interference fringes.

17. Reflection Holograms: reconstruction • A reconstruction beam is shone towards the plate • This beam must be placed at the exact angle the illumination beam was during the recording phase • When this happens, the reconstructed object wave front is then reflected onto the viewer • The image will appear to be inside the hologram for the viewer

18. How a hologram works Steps to How a Hologram Works • Beam splitter, which divides the beam of light into two parts. • Mirrors direct the paths of these two beams so that they hit their intended targets. • Each of the two beams passes through a diverging lens, which allow the beam to become a wide swath of light rather than a narrow beam. • One beam, the object beam, reflects off of the object and onto the photographic emulsion. • The reference beam, which is the one of the two beams that were created by the beam splitter, passes thought the mirror and reflects off the emulsion

19. Achieving a high quality hologram • In order to achieve an image of excellent quality, the darker the room is, the better. • Blue-green safelight as available that cane be used to add a little to a room without affect the finished hologram. surface that can keep the equipment absolutely still. • To make clear holograms, you need to reduce vibration in the air as well. • “Making holograms is a lot like taking a picture with a microscopic level of detail.”

20. Main parts of eye involved in seeing • Cornea, Lens, Vitreous Humour, Optic Nerve, Retina

21. How the human eye works • Light enters through the Cornea, a clear “window” that transmits and focuses the image • Light then passes through the Lens, which focuses the light further, and then passes the image transmitted by light through the Vitreous Humour, the gel-like substance that fills the instead of the eyeball, until it reaches the Retina • The Retina is light sensitive nerve endings at the back of the eye, which receives the light, which forms an image, converting the light into electric impulse • This impulse or message is sent to the Optic Nerve, which transmits the message to the brain, which receives and interprets the image

22. 3D vs. 2d as seen by the eye • 2D images are viewed through parallax created by the eye • neuroscientist BelaJulesz proposed that by tricking the eye in perceiving the parallax, depth can be created in the image in order to see 3D images rather than 2D • Below is how the eye perceives a 2D image:

23. Works like a camera • Like photographs, holograms are recordings of reflected light • A shutter opens and allows a laser to fire a pulse of light, the light from the object beam reflects off of an object • The light from the reference bean bypasses the object entirely. The light from both beams comes into contact with the photographic emulsion where light sensitive compounds react • The shutter then closes

24. The last step • A developed piece of film used to make a hologram does not appear at all similar to the original object. • A dark film or a random pattern of lines is usually visual. In order to turn this frame into an image light is required. • In a transmission hologram monochromatic light shines through the hologram to make an image. • In a reflection hologram, white light reflects off the surface of the hologram to make an image. • The human eyes interprets the light shining or reflection off the hologram as a three dimensional object.

25. Holograms are a new possible medium in art • Art has often been used to communicate messages about issues artists find within society, problems with the world they find unethical and immoral • Holograms could be used to make what would be flat work into more tangible looking, more vivid, and more shocking work, communicating artists’ opinions more effectively with greater impact • It could even potentially replace the current 3D method used in photographs and films; string multiple hologram frames together like film… • Artists can use this art medium to exhibit about and for causes they find worthy • The more popular holograms become, the easier they may be produced, magnifying the benefits • These kinds of artwork can be seen in the Rabbit Holes museum. This is a museum that contains only holographic art, and it is very impressive.

26. Ties to aim 8 • Holograms have a variety of potential uses. If produced more efficiently: • it can store more information than electric or magnetic storage • it could keep a record of objects (engine parts, for example) in their ideal form, kept to quickly locate damage and wear • as holograms capture the light field of an object, than just the light reflected off an object, it provides a new technique at looking at objects in the world, versus, for example, a photograph • it could be used as a new academic visual resource, such as a drawing of the human digestive tract versus a hologram of it

27. Cont... Holograms are used on money to prevent counterfeiting (due to difficulty of reproduction). Theoretically: • This prevents sudden increases in the money supply, and therefore, increases in inflation, and decreases in the value of goods • Without holograms, the gross national income would decrease • This decrease in the country's income could result in decreased funding for or the loss of social benefits, such as community centres, educational programs and initiatives, health care benefits • To counteract this, a possibility is to collect more taxes, such as environmental taxes, taxes that force corporations to be more environmentally friendly; money is raised for social benefits, and/or pollution could decrease • This discourages illegally creating money, an unethical act as the money is not earned