Yea now see I dont want something that will make my laser larger but thiner for close up burning and long range shooting, no something where at 3 feet I will have a basketball sized laser dot. If the correct term for what I am looking for is actualy called a beam expander (strange since I dont want to expand it, lol) than my bad and im sorry but if it actualy is than those things close a crap load of money and I would be looking to build myself one.
xJumper,
Just a note, the "beam expander" is usually just (2) lenses, as explained earlier, and if you reverse the order of these lenses, they become a beam-condenser, (which is what you are asking for, but maybe not what you want). So if you want to focus to a point at long ranges you will need to expand at the lense and focus to a point to overcome natural divergance. But if you make your beam expander removable and reversable, you can fire the laser through the magnifying lense first, and the expander lense will correct the beam into the now thinner beam. For instance, a 2x beam expander will make your beam twice as thick at the pointer, but your dot twice as small at a distance, pop ballons twice as far, reverse your 2x expander, and your beam will be 1/2 as thick as without it, but your dot will be twice as big at a distance, popping ballons at only 1/2 the distance. I started down the exact same road, I want a very thin Blu-ray beam, it is really a trade off.
If you want a less expensive alternative to the $500 beam expander on youtube, you could try one from Lasermate:
http://www.lasermate.com/optics.htm#Compact Beam Expanders
They offer 2x, 3x and 10x, I bought the 10x for $48+ which is way too much loss through the lenses, I would not recommend it for "thermal experiments", you lose like half of your power. When reversed it also makes a 10x thinner beam than with just the Aixiz lense alone, but it spreads out into a haze after about 12ft. Next I would try the 3x, I think these are $38. One note: these are made to screw into something like an aixiz module, except a little bigger, the Aixiz module uses 9mm threads, and these beam expanders use 11mm dia threads. You would have to come up with a mounting method, I am working on one.
Experiment with a monocular, binocular, or telescope to view these effects directly beofre deciding what you want to do.
Laser through the eye-piece=
beam expander
laser through the objective lense=
beam reducer
Alignment is critical, also, I understand reflections from the lenses back into your diode may damage the diode, just a warning.
Hope this helps, Good luck! ;D ;D
Dark Horse
I believe the optics are as important as the electronics.