Need some help/advice

[snowlover91]

I noticed something somewhat odd with my 50mw green laser last night.  On batteries below 1.4v, when I turn it on it is a single, narrow beam.  However, when I use stronger batteries (fresh ones around 1.5v), when I turn it on the beam starts out narrow but then like expands into 2 seperate beams, kinda hard to explain but that is what it does.  Everytime it starts as a single tight beam and then expands into 2 seperate beams.  Anyone know why this could be or what is causing it?  I don't think it affects the power though because about 10 feet away the beam converge again.  Anyone have any advice on what can be done to fix this or what the problem is?

Here are 2 photos that illustrate what I am talking about.

Weak batteries below 1.4v, single concentrated beam.

Stronger batteries around 1.55v (fresh), 2 different beams.

 

[diachi]

Your laser is mode hopping. This means that the TEM ( transverse electromagnetic mode ) of your lasers output is changing. This can be due to thermal problems, or too much power going to the crystals in the laser. In your case it seems like the crystals are receiving too much power from the pump diode, and changing output mode.

There's not really much you can do. You could ask for a replacement, or you could use lower voltage batteries. Or try different operating temperatures.

-Adam

 

[snowlover91]

So how does it produce those 2 beams though? It is brighter on higher voltage though, and it is hard to notice the 2 beams. Pretty cool laser though.

 

[maxkillz]

it's something from the crystals in DPSS lasers, I've seen them put out over 30 beams before. My DX20 green produces 2 beams if the temp drops below 40F or >100F but anything in between it has one solid beam my alpha 105 is a bit more forgiving ;D