Religious experience

[stanwax]

Ive just had one!
Took delivery of a small ammount of stock today from bridge of his line and star pass thru gratings.
WOW
they will be up on the laserwave uk site in the next couple of days with some video clips but here is a taster in the form of a few pics. For something so simple thay are the mutts....

The first image is the star grating with a single white dot (beam) being shone through it.
second shows the line grating with 3 dots - image taken from inbetween 2 of them
and final image is the same projection on a screen
Fantastic.
These will be demonstrated at teh meet mounted on contra rotating motors - get ready!

Rob

[andy_con]

rob got a rough size and price?

[stanwax]

They are exactly 48mm
as for price I am expecting they will be in the order of £25.00
Also I will be looking into a motor drive for them at some point in the future - the ideal setup will be a pair of them contra-rotating very, very slowly

Rob

[James Lehman]

Here's an uninformed question!

Is it possible to make a film that has a color image in it that is somehow like a diff grating and a hologram in one? That is to say, with a static white light beam (RGB at certain wavelengths), could you make what looks like a full color scanned image with absolutely no flicker (not scanned; but rather diffracted) ???

You'd probably have no way to get rid of the "outband" information though... You'd most likely have weird looking red, green and blue images that kinda' lined up to make some weird colored lines.... Hmmmm.

James.

[heroic]

Here's an uninformed question!

Is it possible to make a film that has a color image in it that is somehow like a diff grating and a hologram in one? That is to say, with a static white light beam (RGB at certain wavelengths), could you make what looks like a full color scanned image with absolutely no flicker (not scanned; but rather diffracted) ???

That's called a hologram, and yes, it can be done (though doing it in full colour is very difficult and expensive.)

[soforene]

That's torn it.
Someone mentioned Hologram.

JEM's spider senses will be tingling now ..........

[Jem]

That's torn it.
Someone mentioned Hologram.

JEM's spider senses will be tingling now ..........

Oh Yes... Mention Holograms and i'm there

But to try and answer the previous post (and bear in mind i'm no expert)...

Here's an uninformed question!

Is it possible to make a film that has a color image in it that is somehow like a diff grating and a hologram in one? That is to say, with a static white light beam (RGB at certain wavelengths), could you make what looks like a full color scanned image with absolutely no flicker (not scanned; but rather diffracted) ???

That's called a hologram, and yes, it can be done (though doing it in full colour is very difficult and expensive.)

Called a hologram?... Well, yes and no

Yes, in so much as a hologram is made with a laser and the image can be reconstructed with either white light (reflection hologram) or laser light of the original wavelength used to make the hologram (transmission hologram). It is possible to shift the replay wavelength of holograms but that's for another day.

By illuminating a hologram with laser light (or white light) it's like looking through a glass window and seeing the original item in its original situation behind that window fully reconstructed in 3D.

With a transmission hologram (can also be done with reflection holograms) it's also possible to make another hologram (copy) from the first one by placing another unexposed holographic plate somewhere within the reconstructed image. Thus when this hologram is developed it is quite possible to make an image that straggles the plate (some of the image is in front, or appears to stand out of the plate and some is behind it).

Now, instead of using a second plate you can place a piece of card in the image of the first (transmission) hologram. What you will see is a slice of the image, and as you move the card nearer or further from the first hologram you'll see a different section (slice). So, you wouldn't be able to reconstruct a 3 dimensional projected image on a flat surface, but you could possibly reconstruct a 'slice' of the image although I suspect it wouldn't be very good.

Also, in order to do what you are suggesting you would need a laser with a huge coherence length (read expensive) if you wanted to project at a distance. Incidentally, I am no scientist and by no means an expert on this, this is a fairly simplistic explanation that may be fundementally flawed

Sadly, the Princess Lia hologram from Star Wars is still in the realms of science fiction. However, if you want to see something that is absolutely real take a look here...

http://www.jrholocollection.com/

Or here...

http://www.displayhologram.co.uk/

Inaki does some absolutely stunningly beautiful colour holograms.

Or if you want to learn more about holography please see here...

http://www.holographyforum.org

Colin Kaminski who runs the holography forum has recently become a member here on PL. If you ask the same question on the Holography Forum i'm sure you'll get a more informed and scientific answer

Cheers

Jem

[heroic]

Sadly, the Princess Lia hologram from Star Wars is still in the realms of science fiction.

Yeah, if you're looking for something like that may I suggest that we've had good results from projecting with a conventional LCD projector onto a thin laminar flow of fog from a fog machine... you need a box with three slits in it; you pump fog through the middle one and clean air through the other two, and you get a fog screen that takes projection pretty well. You do need to fine-tune the flow rates a bit though.

We haven't tried it with the laser yet.

[James Lehman]

That's called a hologram, and yes, it can be done (though doing it in full colour is very difficult and expensive.)

I don't mean a film that you look through to see a 3D image. I mean a film that you shoot RGB laser light through that projects a 2D color image.

James.

[heroic]

I don't mean a film that you look through to see a 3D image. I mean a film that you shoot RGB laser light through that projects a 2D color image.

James.

There are many cheap laser pointers that come with exchangeable end caps containing holographic diffraction grating beam-forming optics.

This one, for example:

http://www.ubid.com/Mr._Laser_Inc._5...-c1409-s6.html