Laser project questions

[kurt]

I'm new here - I looked around at a few tutorial threads, but I'm still unsure of a couple of things so I thought I'd ask a question about a project I have (I hope this is the right place to post this - my apologies if it isn't).

I'm wanting to make, in short, a very large laser maze. There will be several hundred feet between mirrors, with 5-6 mirrors (total beam distance will be roughly .5 miles, or .8 km). I'd like the beam to be visible during the day - how feasible is this? I'd like to know what wavelength/power of laser diode I should buy.

I assume I can achieve my goal with a lower-powered green laser, since it's brighter, but it seems that green diodes are harder to come by (and thus more expensive). Is this true? If so, should I choose red/blue, and what power would be necessary?

I don't mind soldering, milling, etc. so I'm really only concerned with the diode. Any thoughts on this would be appreciated.

 

[The_Muffin_Man]

I'm new here - I looked around at a few tutorial threads, but I'm still unsure of a couple of things so I thought I'd ask a question about a project I have (I hope this is the right place to post this - my apologies if it isn't).

I'm wanting to make, in short, a very large laser maze. There will be several hundred feet between mirrors, with 5-6 mirrors (total beam distance will be roughly .5 miles, or .8 km). I'd like the beam to be visible during the day - how feasible is this? I'd like to know what wavelength/power of laser diode I should buy.

I assume I can achieve my goal with a lower-powered green laser, since it's brighter, but it seems that green diodes are harder to come by (and thus more expensive). Is this true? If so, should I choose red/blue, and what power would be necessary?

I don't mind soldering, milling, etc. so I'm really only concerned with the diode. Any thoughts on this would be appreciated.

This section is fine...

A laser maze? Im not quite sure what this is...do you mind elaborating?

Your best bet would be a green module from o-like. This is the homepage: o-like.com, but you should also maybe check out their 100mW tec cooled unit. Industrial TTL Green laser Module 100mW w/TEC£­>5¡«500mW green laser module£­>Laser&lighting products£­>www.0-like.com. I am assuming you will want to leave this on for a while. If you do then get the TEC. OR you could just throw a green module into a heatsink...that would work too.

Feel free to PM me if you want.

 

[kurt]

Thanks for the quick reply. I don't mind elaborating...

The setup is just a laser beam originating from one particular spot, but being bounced around a bit by mirrors at various angles until it ultimately reaches it's final destination. The puzzle will actually involve placing the mirrors in their designated spots so that the laser can reach its final destination (where the beam will be diffracted to form an image that is the answer to the puzzle).

It's actually not necessary for the beam to be running for any single time longer than 30 seconds (basically, long enough for them to see the beam and figure out where the next mirror should be placed). I'm mostly just worried about beam decoherence (and thus visibility loss) due to how long the beam path is. I'd like the beam to be visible over the entire path if possible. But you think 100mW green would do it?

 

[dr-ebert]

Note that a beam that's visible in daylight can blind you instantly if it hits your eye (and definitely will damage it) - playing with mirrors isn't really recommended. This project might be feasible in an enclosed space with a smoke generator keeping the air slightly hazy; out in the open, not.

Beam divergence is typically 1mrad - worse (more) for greens. That's 1mm for every m travelled. For the distances you're talking about, you'd need a beam expander (reverse telescope) that widens the beam to about 20-30mm diameter, proportionally improving the divergence.

 

[kurt]

I'm not too worried about random strangers passing through the beam, as the vast majority of the beam path will be 50-100 ft above ground. That's a good point though concerning the safety of the participants though - would safety glasses help? If not, I will probably change the setup a bit.

If I increase the beam width by 20-30x, won't that decrease the intensity by a factor of that squared? Wouldn't that require me to get a much stronger diode than 100 mW if I want the beam to still be visible? Or would that still be visible?

Thanks for the help.

 

[KGB_Productions]

For a project like this I would think that you would need more than a Watt of green for this to actually work, to be visible in daylight, from 50-100ft in the air, with the beam expander......correct me if im wrong but 100mw doesn't seem right..........:thinking:

 

[Kenom]

your correct. You'd need a massive amount of laser in order to remain visible during the day and being deflected with so many mirrors over such a large area. Just not feasable. It will work in an enclosed space with smoke.