Holograms

It is argued that a hologram can be hand made by scratching a piece of plastic.

Produce such a ‘hologram’ with the letters ‘IYPT’ and investigate how it works.

Outline

1) Theory - Basics of holography

2) Predictions and expectations

3) Information gathering

4) Experiments

5) Final product

6) Summary

Theory

Holography is a technique which enables three-dimensional images (holograms) to be made. It involves the use of a laser, interference, diffraction, light intensity recording and suitable illumination of the recording. The image changes as the position and orientation of the viewing system changes in exactly the same way as if the object were still present, thus making the image appear three-dimensional.The holographic recording itself is not an image; it consists of an apparently random structure of either varying intensity, density or profile.

Predictions and expectations

- Not actual hologram

- How to hand make hologram

- From simplest to more complicated

- How these ''holograms'' work

Information gathering

Use a marker to draw a simple pattern such as the letter "V" near the lower edge of the plate. This will be the image that we'll encode onto the surface. Draw your "V" less than 2 cm tall. Set the spacing of the compass points to a couple of inches. Place one point on the tip of the small "V" at the bottom of the plate, and *gently* drag the other point lightly across the plastic so you make an arc-shaped scratch that looks something like the figure below. This is your first scratch. It helps to tilt the compass so the point trails across the surface and does not dig in or chatter. The scratch should be easily visible, but not extremely deep.

Information gathering

The scratch should be dark and polished, not white and dusty. It should show a small highlight when viewed in sunlight or under a pointsource illuminator such as a small, clear light bulb. Now, while keeping the dividers at exactly the same spacing, place the point at a different place on the little "V" and use the other point to make a single circular scratch as before. Do this again and again, ten times or more, each time placing the point on a different spot on the little "V". When completed, the overlapping arc-shaped scratches should look like you've swept a bit of sandpaper across the top of the plastic plate. The little letter "V" should be full of holes made by the other point of the compass.

Experiments

1. Scratch - virtual

Simulation made with Algodoo

Final product

2. IYPT hologram

Final product

Summary

1) It is not actual hologram yet way how to store 3D image to 2D one.

2) Every scratch is changing light's direction and only one part is lightened from any angle.

3) Individual lightened parts make an ilusion of 3D image.