Best Laser for sending signal to space?

[Kartracer00]

This makes no effing sense. someone slap this kid. please.

I mean, I'm sorry for being so rude. But can you blame me after stating such a ridiculous task?

 

[Moebius]

That is Awesome! Thanks man!! That's what I had in mind. Then as the craft comes closer, the beam will eventually become visible (if the craft has that capability. hehe).

Does anyone have any ideas on how a build like this would work (link below). If so, I will see if he will make me a blue or green one.

>>>> http://laserpointerforums.com/f39/sold-2-3w-445nm-lighthound-minisabre-77083.html

You make it sound like you want to communicate with UFO's by lasing them with 2.3W's.
Lasers are serious. Especially at the power levels your talking about.
Not a good choice as a 1st laser. Get your feet wet first.
Once you see what 150mW of green looks like, you'll be hooked.
And forget about the aliens ok?

 

[Multimode]

Amateur Radio guys have set up laser communication links (google)
There are references of 43Km and 100Km + CW (morse code) link ups.

Search "free space laser communications" - lots of clever people have worked on this ;-)

 

[madmacmo]

High-fidelity audio signal successfully transmitted / received at a distance of 6.5 miles employing only a cheap red laser pointer as the light source and a readily available photodiode as the detector.
Light and sound Post #25

Same cheap red laser pointer sucessfully observed at 22 miles
Music on a Light Beam

How far can we transmit high-fidelity audio with a cheap laser pointer (and other cheap equipment)?
These photos show some DX testing with the cheap laser modulator, receiver/demodulator, and associated (cheap) optical equipment (click the links above). Tests were made at 80' (24m), 500' (150m), 1200' (365m), 1 mile (1600m), 6.5 miles (10.5km) and 22 miles (35km). The tests were generally successful to the 6.5 mile test distance, though at 6.5 miles the sound was less than broadcast quality (future hardware enhancements may improve that).