Where are all the holograms?

These are all of the old posts from the first two years of the forum. They are locked.
Updated: 2005-03-28 by HoloM (the god)
Greg G

Where are all the holograms?

Post by Greg G »

Interesting article today in Laser Focus..

" Single fixed laser crystal emits red, green, and blue light

A solid-state laser containing a single piece of active (gain) material that simultaneously produces red, green, and blue (RGB) light could be valuable for full-color image projectors. Typically, RGB laser light is produced by a complex arrangement of laser rods and nonlinear crystals. A version of single-crystal RGB laser has been developed by scientists at the Université Claude Bernard-Lyon (Villeurbanne, France) and the Chinese Academy of Science (Fujian, China) that relies on neodymium-doped gadolinium aluminum tetraborate (NGAB).

Pumped with pulsed light at 744.7 nm and 10-ns pulse duration (2.5 mJ per pulse), the laser operates at the dual wavelengths of 1062 and 1338 nm. Red light at 669 nm and green light at 531 nm result from self-frequency doubling of the laser's two wavelengths, while blue light at 480 nm results from self-sum frequency mixing of the pump and the 1338-nm laser light. All colors are emitted at the same time and at a fixed crystal orientation. For experimentation, a dye laser provided the pump light. The NGAB crystal was 4.9 mm long; for RGB output, phase matching was not exact for any of the colors. "


Start saving, folks...
Colin Kaminski

Where are all the holograms?

Post by Colin Kaminski »

Wow!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

" phase matching was not exact for any of the colors"

What does this mean?
Dinesh

Where are all the holograms?

Post by Dinesh »

I suspect the coherence length was pretty low. As you add frequencies, you shorten the coherence pulse. Also, if the phase relationship between the beams was not maintained, ie no phase correlation mechanism between frequency components, the coherence would drift as the relative phase between each component drifted.
Greg G

Where are all the holograms?

Post by Greg G »

They didn't say it worked well, just that it worked..

It's an interesting material but getting such disparate wavelengths as single mode lines out of a single optical system has a number of engineering issues to overcome. But it's a cool concept and something to keep an eye on for the next few years.
Dinesh

Where are all the holograms?

Post by Dinesh »

I was half wondering if it's possible to put in three etalons in-line. It'd kill the power a lot but it'd take full color out of the lab and onto the sand-table.
Greg G

Where are all the holograms?

Post by Greg G »

It might take a bit more work than that to make a useful laser. I'm willing to wait a bit. My 744.7nm pump laser is in the shop anyway
( joke ). But 3 colors out of one box is a nice thing to dream about.

I was almost tempted into building a Helium Selenium laser years ago ( I had a Liconix HeCd in one of my work junkboxes ). Kimon makes those but I don't think they ever managed to make a single mode version.
Sergio

Where are all the holograms?

Post by Sergio »

"But 3 colors out of one box is a nice thing to dream about."
Simultaneous 3 colour generation where obtained with dye lasers, white laser light generation is possible, I guess around 1973 the first simultaneous liquid dye laser line generation. However requires high maintenance and uses pumps, etc.
Greg G

Where are all the holograms?

Post by Greg G »

And I recall the dye as being a very nasty one to work with.. My first adventure in dye lasers was with Rhodamine 6G and Fluorescin
( red/orange and green ) based lasers.. Some of the perks of the stranger dyes were highly toxic, carcinogenic, teratogenic and hosted in things like DMSO and ethylene glycol. Even when water based, one leak and your hands are dyed fluorescent colors for weeks.( Made it tough getting into clubs on weekends.) I never heard of anyone doing holography with a dye laser but I suppose deep pockets can make things happen.

Helium Selenium sounded pretty but I'm not sure it ever made a real commercial laser. Even "simple" HeCd was a pain.
Tom B.

Where are all the holograms?

Post by Tom B. »

Well said. I generally agree with your dismal prognosis, but invite you to entertain some of the following fantasy scenarios:

1) The Art world learns of holograpy's outcaste status, and holds a benefit concert. They have lasers all over the place and drag up some grizzled holoveterans to the stage who make a live holo of Madonna's conical appurtenances. We are then inundated with holographic CD cover art containing various projecting thingies from various artists. Suddenly everyone wants a hologram of a thingie, preferably pierced. Public taste is weird.

2) Holoprinters become a real product () and computing capacity advances to allow real-time previsualization of the result. Playstation 3 is coming soon, so maybe this is not so far off. Suddenly, the sky is the limit as to what can be depicted in a hologram. No more porcelain cats, and no more multiple HOEs needed to get abstract effects a la Rudy Berkhout. 99.9 percent of the results will be crap, but because so many more people have access to the technology, we are bound to see some beautiful and startling stuff.

3) High power pulsed RGB lasers become available at Radio Shack. They are sold as replacements for their Xenon strobe lights - they are brighter, cheaper to make, and (accidentally) coherent.

4) Someone discovers an easy way of smoothly applying and stabilizing DCG to make bright, clean, big, permanent holograms. And drastically boosting broadband senstivity without getting into seriously toxic chemistry. This formula works really well with the Radio Shack RGB lasers.

5) Someone else discovers how to practically get better depth from reflection holos. Kubota's work might be helpful as a starting point.

6) Some artistic genius adopts the orphaned holographic art, creates unforgettable holos of kittens and dinosaurs doing wacky things, and says "Contemporary elitist sterile art sucks - I propose to do better, and I invite you to join me". Also - "I'm glad I kept my day job. It gives me a break from the insanely stressful business of making great art, and it pays the rent, too". The holographic art revolution is coming soooon...
Dinesh

Where are all the holograms?

Post by Dinesh »

"4) Someone discovers an easy way of smoothly applying and stabilizing DCG to make bright, clean, big, permanent holograms. And drastically boosting broadband senstivity without getting into seriously toxic chemistry. This formula works really well with the Radio Shack RGB lasers."
So you have a spy in my lab. I knew that spider lurking up there in the corner had to be artificial!

7) Some Physical/Chemical genius discovers how coat a plastic film with a material with sensitivies of nano-joules/sq cm and create a filter such that it converts ordinary daylight into coherent light. Some marketing genius then puts these films into a little box with a shutter in it and mass markets it to the public. All they do is snap the holo with the click of a shutter and send the film to a lab for processing. Now everyone is snapping away, mostly of Aunt Edna At the Beach or baby pictures, er..holos. Someone discovers that these little boxes can be used to create Art and sells postcards, ..er holocards, of the Grand Canyon or the Eiffel Tower or some such landmark.

7a)Some genius discovers that you can put bags of developer inside the box and arrange a system so you squeeze the film out between two runners. This action automatically develops the hologram. Now you don't need to send the film to a lab for development. You can make Instant Holograms!
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