3D Holograms

[k-k]

Hi All,

 

I was wondering if anyone had any feedback on an idea I have been playing with i.e. is it possible or completely impossible due to the laws of physics? Has it been done before (I can't find anywhere)? Is it completely unachievable? If this is a rubbish idea please feel free to say.

 

The idea revolves around being able to focus a small beam of light onto a given xyz co-ordinate in the atmosphere. As can be seen from playing with magnifying glasses and the sun as a child, its possible to focus light rays onto a point to such a degree of accuracy that the point becomes small enough to burn. If one was to take a light source (LED or something) and control a lens or mirror to focus the light onto a given point in the atmosphere, it might be possible to generate a point of light quite small? Maybe the size of a "pixel" when thought of as an image.

 

Obviously for the focal point to be visible to the human eye a reflective material would need to be present, the reflective material would need to be free standing in space, possibly some form of particle. I was thinking a form of smoke.

 

Would it be possible to continually refocus the beam of light onto different points in the smoke (maybe turning the light on and off) to form a 3 dimensional image. Obviously the focal points would need to be rendered within a very short time frame of each other to give the impression of a single image, I think that some form of raster scanning could be used to render the image. The addition of multiple beans of light could be used to create the points of light faster.

 

Possible obvious flaws I can see are:

1. Due to the smoke particle reflecting in all directions the point the focused point would probably become blurred, however if the image is large enough and the focal point strong enough in contrast to the glow, the human eye would compensate.
2. The bean of light, on its way to being focused, will also need to travel through the smoke particles illuminating them slightly, however again I hoped the contrast between the focused light and this noise light would be enough to get round the issue.
3. The beams of light would need to be shifted and focused at a extremely fast rate, which may not be achievable. I was thinking of using a lens that is generated by holding liquid between two transparent sheets. The volume of the liquid could be controlled to create a lens? Or shaping a mirror with an electro magnet.
4. Obvious problems with the smoke being not dense enough, too dense, disturbances in the atmosphere etc.

As I have no physics background, I thought I would ask the experts on this forum as I've been wondering if this is theoretically possible?

 

Thanks for your time.