Having some issues focusing my first laser.

Basically I just completed building my A140 diode laser inside of a C6 host with a 1.2a driver. When I put the batteries in the first time (2x 3V CR123A), I was able to focus it for a split second long enough to burn a hole right through a piece of paper that I had laying around. After the laser lost focus for a split second, I was not able to focus it to the point where it was able to burn anything. I burned the paper from a distance of about three feet, but I can't even do that from a distance of one foot anymore and I also tried lighting a match or popping a balloon, both of which failed. I was wondering, does anyone have any idea what could be wrong? I can add pictures if anybody wants to see.




Without Lens:

Focused?

Also, when I turn the lens around, I feel like it start to get really bright, but not exactly focused and as I turn the lens it starts to focus, however, when I almost get it focused perfectly, the lens ends up falling out of the diode module.

What are you expecting? A perfect dot? You do realize this is a multimode diode and even "perfectly" centered it will be a 'bar' not a dot

How focusing works (in this case) is as you bring the lens closer to the diode (tightening it) your laser will become more and more focused to "infinity". When it is at "infinity" you'll have a beam and the dot will be at its smallest for the longest distance. because of the large power density with 1W+ 445 lasers at "infinity", you can burn objects much farther away (2-3'). If you were to slightly loosen your lens while your laser was focused to "infinity" you would see the beam get really thin. That spot is the focal point where the energy density of your laser is at its highest. with a normal lens like the one you have you can only do this from about the end of your lens to about 8" on the beam. beam expanders allow for longer range focused burning. never operate your laser with out the lens. it can reflect back into itself which will kill the diode. also keep the lens on the laser because dust and other debris will get on your diode window. this debris can then get burnt on which will give you an ugly beam profile when you de-focus it and possible power loss. it is also a good idea to keep a lens cap on your lens for the same reason. If the lens is not staying firm in the module wrap it with a little bit of Teflon tape.

What are you expecting? A perfect dot? You do realize this is a multimode diode and even "perfectly" centered it will be a 'bar' not a dot

Click to expand...

yep noobs have perfect knowledge of Transverse electromagnetic modes. Focusing is somewhat abstract. It took a while for my friends to understand it.

If that is an acrylic lens which usually come standard on those diodes you should not use it. the optical density of the laser can melt the lens onto your diode killing the laser. be sure to have a glass lens. you can get a 3-element one which will give you a more round beam and better divergence. on the other hand you could get a single element lens like a G1/G2/G9/T9 which are expensive but will give you a 30% increase in power at the cost of some divergence and an ugly beam with a box around it. lastly there is the o-like lens which costs 10% of what a "g-lens" costs and works 99% as well.

Also, I can't seem to focus the laser to infinity

And could you possibly link me to the O lens? I am using an AR lens right now specifically designed for 445nm diodes, also it did work once before, so I am not sure that the lens is the issue.
(http://www.survivallaserusa.com/445nm_AR_Coated_Standard_Glass_Lens_Assembly/p1667092_7862037.aspx).
I also noticed that the back of my diode managed to completly melt everything, causing a huge mess. Could this be the problem? Regardless, I will probably try to clean it up a little.

This diode looks LED.:cryyy:


Should look like this.


What driver are you using? I see this a lot with that DX LED driver.

Melted everything means horrible heat, which comes from a LED diode, which can come from a few things but sounds like you caused it. Expensive mistake. .....

I am using this driver: Survival Laser Driver. Also when I bought the diode, the seller on ebay listed it as a A140 405 nm blue laser diode, so would the fact that it is LED be my fault or the seller I bought it from? The diode I bought : http://www.ebay.com/itm/1W-to-1-5W-...502?pt=LH_DefaultDomain_0&hash=item1c3fe26b4e.

Edit: I also had to refit the diode into the module after the first test, as it had fell out. I assume improper heatsinking played a large part in the melting of the wires in the back.

You can also get them from techhood for $8.90 with free shipping405nm 445nm 515nm Laser Lens MP9X9MM Laser Collimation Glass Lens 1 Pcs | eBay

It is 100% your fault. If the diode fell out of the module then that means it was never pressed in properly, thus no heat transfer, thus fried diode

Alright, thanks for the input.