Laser + Reflective Surfaces Art Installation Concept

[pbtimo]

I have no experience with lasers or light shows, but I do art installations and have recently been brainstorming about incorporating lasers into some projects.

Here is a super sloppy/brief sketch of the fundamental concept:
http://imgur.com/pzuc8t9

I know lasers shining directly back at themselves can cause damage. Are there options other than rearranging rotational/angular parameters to prevent this? Low powered lasers? A certain kind of reflective surface? Some kind of in filter in front of the laser?

Basically, is there anyway I could make this work? Or do I need to go back to the drawing board?

[swamidog]

back reflection is only a problem with diode lasers. it's not an issue for ion lasers such as HeNe, Argon, and Krypton.

instead of rotating the lasers, i'd suggesting keeping them stationary and move the beams by rotating mirrors or prisms.

I have no experience with lasers or light shows, but I do art installations and have recently been brainstorming about incorporating lasers into some projects.

Here is a super sloppy/brief sketch of the fundamental concept:
http://imgur.com/pzuc8t9

I know lasers shining directly back at themselves can cause damage. Are there options other than rearranging rotational/angular parameters to prevent this? Low powered lasers? A certain kind of reflective surface? Some kind of in filter in front of the laser?

Basically, is there anyway I could make this work? Or do I need to go back to the drawing board?

[pbtimo]

back reflection is only a problem with diode lasers. it's not an issue for ion lasers such as HeNe, Argon, and Krypton.

instead of rotating the lasers, i'd suggesting keeping them stationary and move the beams by rotating mirrors or prisms.

Awesome! Thanks for the quick reply. Do you have any suggestions on exactly what would work best for such a project? Ideally I'd like the best "bang for your buck" in terms of brightness. I plan to have some kind of smoke machine to enhance the visibility.

[silentgloves]

You could mount the laser so that it was firing perpendicular to the reflection space, then use a mirror mounted at a 45 degree angle on a motor axis to provide the rotation. This would reduce your rotational mass significantly, especially if using a DPSS laser.

[buffo]

Do you have any suggestions on exactly what would work best for such a project?

What, exactly are you trying to accomplish? Do you want the beams to be rotating in the vertical plane like spokes on a wheel? If so, then in your original drawing - as the lasers rotate the reflected beams will sweep left to right as the central laser(s) rotate clockwise. Is that what you want, or are you looking to have a static display of solid spokes?

Another issue that needs to be addressed is audience safety. Do you intend to allow the audience to approach this display and/or interact with it in any way? If so, this will place significant restrictions on the amount of power you can use, making the effect far less impressive. On the other hand, if you can keep the audience at least 2 meters away from the display (say, with a physical barrier like a rope or a railing), then you are free to use more power, which will make the effect far more impressive visually.

Ideally I'd like the best "bang for your buck" in terms of brightness. I plan to have some kind of smoke machine to enhance the visibility.

Fog will be a big plus. Reduced lighting in the area will also help a lot. In terms of perceived brightness, green is the best color to use, as the human eye is more sensitive to that color. However, given that 445 nm blue laser diodes are very cheap right now, it *might* be cheaper to use multiple blue diodes instead, even if blue doesn't appear quite as bright to the human eye. Once you've explained the effect a bit more we can run the numbers to see which laser makes sense for the display.

Regarding back-reflection, even if it was an issue, it would be trivial to alter the geometry of the rig slightly so the reflected beams just miss the central hub where the lasers are mounted. (That is, angle the beams so they bounce off the outer mirrors at anything other than a perfect 90 degree angle, so the beam is no longer perpendicular to the mirror plane.)

Adam

PS: It does sound like an interesting concept. Is this going to be part of a larger artistic display?