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This has been done before, IIRC Samsung released one of the first TV quality raster scanning system for laser shows.

Basically a standard laser show setup uses multiple lasers (to get your RGB) combined into a single beam then passed through a device, such as a PCAOM, which acts as rather like a programmable colour filter. (this isn't the only way it can be done with solid state lasers).

Two sets of mirrors can be steered in the X and Y axis to draw your shapes, beam effects, etc.

In the case of a TV or other raster displays the beam is steered much like you would an electron beam on a regular TV. It scans a horizontal line, moves down scans across, repeat. You can switch the direction of the scan (left to right, then right to left) on alternating lines to speed up the scan rate.

Wikipedia has some info on Laser TV's in general: http://en.wikipedia.org/wiki/Laser_TV and LaserFX has some info on PCAOM's if you're interested in the older tech: http://www.laserfx.com/Backstage.LaserFX.com/Archives/Archives6.html

Early systems actually used multiple projectors overlapping or drawing the first 3rd, 2nd third, etc of the image to make up for slower scan rates.

The "time tunnel" effect is always a crowd pleaser. Drill a hole in a penny and press it onto the shaft of a small DC motor. (It needs to be almost, but not perfectly, perpendicular to the shaft.) Glue a small mirror (1" square or less) onto the penny. Turn on the motor and bounce the beam off the spinning mirror. Add some fog to the room and dim the lights, and you've got a very cool effect indeed. (Wrap a rubber band around the barrel of the laser pointer to keep it on, and tape it into position near the spinning mirror.)

Or you can build two spinning mirror assemblies and generate lissajous patterns. (Think: Spirograph)

Or use some hot glue to tack a tiny mirror onto your speaker's woofer. Bounce the laser off the mirror while you play loud music, and you'll get all sorts of wierd patterns.

Or lay a CD-ROM on your turntable (you do still have one, right?) with the reflective surface up, and bounce the laser off the disc. (The narrow tracks act like a diffraction grating, splitting a single beam into multiple beams.) Slowly rotate the turntable platter (especially with the disc slightly offset from center) to get more effects.

Have a look at my site for some idea of the types of effects you can produce.

Here are a few other sites that might give you more ideas:

LaserFx.com

Sam's Laser Faq

You can do the "gas only glows at intersection of two beams" thing by using a two-photon upconversion process. For example, certain molecules can absorb 2 IR photons and emit 1 visible one. That's easier said than done under the best of circumstances, and may be impossible in a gas.

It's been done in a glass by these people.

a long time ago my uncle told me about how some of his friends at bell labs used to shoot high power lasers into the sky to "paint" the clouds. of course nowadays folks do it for laser shows for outdoor concerts etc...

Actually, the Hitachi one seems to be spinning a flat plane, rather than a screw... The screw based method is described here

Yeah, I saw that woman with the rare-earth doped flouride glass at SIGGRAPH '97 or so. Just looked her up on google and found a name and familiar picture: Dr. Elizabeth Downing. Further googling turned a website for her company, 3DTL.

There was a flurry of info about it in 1997 and not nearly as much since then. Did it go private or did it fold? Further googling describes 3DTL getting a $1.9 million NIST grant in late 1998, and a $340k grant in 1999. Not much visible info since then; I supose you could call the phone number on their website to find out more. I recall one key problem being the small size of the laser-addressable cube. There are probably problems aligning lasers as you scale up in size, but this is speculating based on 5-year old memories.

I ran across a nice survey paper motivated by the problems with rotating displays that discusses a lot of the static volumetric displays including Dr. Downing's.

--LP

Yeah, I saw that woman with the rare-earth doped flouride glass at SIGGRAPH '97 or so. Just looked her up on google and found a name and familiar picture: Dr. Elizabeth Downing. Further googling turned a website for her company, 3DTL.

There was a flurry of info about it in 1997 and not nearly as much since then. Did it go private or did it fold? Further googling describes 3DTL getting a $1.9 million NIST grant in late 1998, and a $340k grant in 1999. Not much visible info since then; I supose you could call the phone number on their website to find out more. I recall one key problem being the small size of the laser-addressable cube. There are probably problems aligning lasers as you scale up in size, but this is speculating based on 5-year old memories.

I ran across a nice survey paper motivated by the problems with rotating displays that discusses a lot of the static volumetric displays including Dr. Downing's.

--LP

I spoke with a friend a while back about some work with multiple plane 3D display units a while back. Using Google, I found a few people that have multiple (arbitrary?) layers of depth using lasers. Yes, this is different than LCD and functionally more difficult, but interesting nonetheless.

The idea is to send multiple beams into a glass cube. When beams interesct, they flouresce. By controling the way the beams enter the cube, one can create a volumetric display. There is an article here about some work done by some Stanford folks, and a somewhat related presentation here from some Berkeley folks.

(also searching, I found the there was an article about Actual Depth here on /. a while back.)

Technically speaking this isn't quite true - it depends on what your lasing medium consists of. While each colour line emitted will be monochromatic, a single laser is capable of producing multiple lines.

In the case of a Krypton or Helium Neon ion gas laser you will get a single line out (usually, but not necessarily, red for either of these).

However, if I look at an Argon laser with apropriate optics you get primarily Blue and Green (514nm "Green" and 488nm "Blue") lines (with combinations in between). If I put a prism to the output of my little American Laser 60x I can see 7 individual lines - 5 are of such lower power as to be virtually useless, but the primary Green and Blue are strong.

Then if you look at a Copper Vapor laser which works by evaporating copper you get two lines: an emerald green and *gold* (this type of laser was made famous during the Pink Floyd Division Bell tour).

Newer solid state are very much single line. If you ever see a very harsh green beam you are probably looking at a Nd:YAG laser. The new solid state stuff is really looking promising... much more reliable with a much longer lifespan. Now, if they could just get the Blue solid states more powerful reliable we would be laughing. A low to mid powered white-light lasershow that could fit in a briefcase! On the down side though, typically much lower power output than their ion cousins (and the YAG green is, in my opinion, really nasty).

Could almost make me miss lugging 909's around... :)