Prometheus Fusion Perfection

Specs: OD 6+ @ 690-1300 nm, OD13 @808nm specifically. For when you have gratuitous amounts of energy. 

For the record those OD3 @808nm laser safety googles are INSUFFICIENT for the power of this laser. I’ve ordered these glasses, which are OD 6+ @ 690-1300 nm, and are OD13 @808nm specifically. This is 10,000,000 X the protection of the OD3 glasses. They are also glass which can withstand a direct hit much better than polycarbonate. Shout out to my peeps.

So the next move is to attempt to laser weld two pieces of steel. Having computer controlled laser welding at our disposal will be indispensable for constructing the core (beginning with welding the lids to the chassis) and the vacuum chamber (welding the chamber itself, welding various feedthroughs). I think we have enough wattage to laser weld stainless steel, although at a slow rate.  However, we still need to focus the beam, which is especially challenging for diode lasers that produce a bar beam like this:

In my research, I found the back story to the lasers I picked up. Looking at the beam path illustration, these units correct for some of the diode array’s problems with divergence and astigmatism, so the output of the diode is a rectangular beam that focuses to a 1.5 cm long line about 15 cm beyond the output aperture.  So we are working with a well columnated beam, but it’s rectangle, not a circle. 

I think the easiest route to a top hat beam would be to focus this bar beam into a single thick core multimode fiber optic cable which results in a perfectly circular Gaussian spot, and an easy way to deliver the beam to it’s target where it would pass through a simple circular focusing lens. Challenges include sourcing the correct fiber optic cheaply, cleaving the fiber optic correctly, and aligning and focusing the bar beam into the fiber optic. This process would benefit from a Laser_beam_profiler, so you can find the sweet spot with focus and alignment for max transmission through the fiber. 

Here is a good overview of the basics of laser welding, including weldability of various materials.

Just received 3 650nm 5mW laser module.3.2V to with lens 650 nm.

I got these to a) play with and b) learn about beam paths:

These are safe as long as you don’t look directly into the beam: