My greenie

I've just received my first green laser from FifthUnit. It is the 30mw unit. http://contents.fifthunit.com/html/products.5th/sku.91.html

First thing I noticed is that it is fairly substantial in the hands. Pretty good construction and came in a padded metal case. The beam is tight and stings the skin of my forearm in 2 seconds. I've tried the popping the ballon bit and after 15 seconds - nothing. I then applied black sharpie on it and at 8" the ballon popped in 1 sec. Does'nt spark a match head in 15sec at 12". I ordered the unit on Sept 6, and picked it up from the po today, Sept 21.

Can't wait for night fall.

Okay, so after playing with the laser for a while I noticed that the beam separates into 3 (4 sometimes) tinier beams. I then turn it off and try it again and it is fine. So it does this intermittently. I am set to return the unit however I would like to know from others more laser knowleadgeable folks about what may be causing this.

thanks in advance for any input.

Sounds like a mode problem. Send it back.

https://www.candlepowerforums.com/threads/130678&highlight=MODE

It sounds like your laser might be mode hopping, which usually happens if it's over-driven or inadequatly cooled. see http://www.mrl.columbia.edu/ntm/level2/ch02/html/l2c02s07.html for info on mode hopping.
I suppose your options are to either return it, or open it up and try to fix it yourself. If you opt to fix it, you might be able to use some arctic silver heatsink compound to produce a better heat distribution, or you could look for the trimmer pot and turn it down a bit. That would mean a less powerful laser, but one that should be stable.

Do a search on these forums for "laser mods" for more info. Your's looks similar to a leadlight 110 I think.

That's a great link.

Wow! the lasers look cool!

wells05 said:

That's a great link.

Click to expand...

i wish i could understand it:huh2:

Hmm, well to put it simply we're talking about interference patterns. A diode laser that's too hot or cold can start to frequency shift, producing light of differing wavlengths. If two or more sets of waves cross each other, they can cancel each other out in some areas, and reinforce or amplfy each other in others. Heres an example: If the crest of the wave is amplitude "1" and the trough of the wave is amplitude "0", take the following 2 waves and see how they combine to make a 3rd: That is a poor 2-dimensional example, but shows how you can get different wave patterns when 2 waves with different frequencies interact. If you extend that to 3 dimensions, you can get the funny pictures in my earlier link.

Edit: found a cooler explanation here:
http://en.wikipedia.org/wiki/Interference