Holography

[johnfp]

Hello all. I make holograms as a hobbies. If anyone decides to take this great challenge on as a project I am fully available for free consultation via e-mail. My e-mail is
holograms3d at yahoo dot com.

[Pyrotex]

Originally Posted by johnfp

Hello all. I make holograms as a hobbies. If anyone decides to take this great challenge on as a project I am fully available for free consultation via e-mail. ...

Hello John!
Welcome to Hypography!
Now, technically speaking (which I do rather often) we prefer folks not to show up and immediately "spam" their website and email addys. However, the subject of holograms is quite fascinating, and so --- JUST THIS ONCE --- I'm going to disarm the Hideo-Cyber Slamotron and not vaporize you.

On condition ( !!! ) that you hang out with us for a "while" and engage in a discussion on holograms, what they are, what they can do, other holo-trivia, answer a few questions from our knowledge-thirsty members (including moi!) and otherwise spread some friendly education.

What say ye?? Or do I have to re-activate the Hideo-Cyber Slamotron??

[johnfp]

Well sure, I love to talk about holography. I was on here some time ago and was avid in my participation. Been busy for months but I think I am finding time to re-aquaint myself with you all. Thank you for the welcome. Ask away.

[johnfp]

Should we start the general discussion in the Physics section and leave this one for questions for homework and projects?

[lemit]

Many years ago, I supervised a student who had done holography at Lake Forest, Illinois, in a special project. He tried to explain to me how holography worked, and failed.

I hadn't taken the trouble since then to research holography the way I could have. I hope you'll help me learn more.

But first, Pyro, I'd like to see that Hideo-Cyber Slamotron. How does it work? Do you have a website where I could buy one?

--lemit

[johnfp]

I have decided to start a thread in the physics section and leave this thread for helping with homework or projects that others may be actually doing. Read the basic intro for holography in that section and feel free to ask any questions you may have. Hopefully my corporate decision to format the sections this was passes the Hideo-Cyber Slamotron test.

[lemit]

So I don't get to find out how the Hideo-Cyber Slamotron works?

--lemit

[Pyrotex]

Originally Posted by lemit

So I don't get to find out how the Hideo-Cyber Slamotron works?
--lemit

Some day, Lemit. When you're older.

John, I have a question for you. I know in principal how a hologram is made. I also know that in the F-16 Falcon fighter there is a Heads Up Display (HUD) so the pilot can look straight ahead out the cockpit and see his navigation "tell-tales" floating out there.
However, to achieve this, the engineers originally needed a very large lens (say, a foot across) with a very short focal length (a thick lens) to bring the tell-tales into focus at infinity.
There was no room for a big thick lens.
So, they made a hologram of the big thick lens.
The hologram (as I understand it) is a thin plastic film that is stuck to the cockpit glass in front of the pilot's face.
And SOMEHOW, this hologram of a lens is made to function EXACTLY like a REAL LENS.

How do they do that??

[johnfp]

All real holograms (not the star wars fake stuff) acts as a lens to take the illuminating light and focus it to the wave front of the original object light. This is done by all those interference fringes being captured in the emlsion.

So to explain simply, think of a fresnel lens. It is thin yet acts as a thicker lense due to the groves. Well it's basically the same principle in manking a Holographic Optical Element (HOE). But instead of etched groves you have either dark and light groves (fringes) in silver halide or two different types of groves (fringes) with relation to their index of refraction as in Dichromated Gelatin (DCG). Most HUDS and HOES are made from DCG as they can approach replay efficiency of 95%.

DCG is what I have been playing with now for years. I make my own emulsion and coat my own plates. My avitar is a hologram I made and you can see how bright it is.

[Pyrotex]

Thank you! I actually understood that!

Your avatar looks like a small bottle, with the words, "Drink Me".