Waterproof laser - reef application

[andyman]

To follow up with my previous requirements for killing pest in a reef tank.
2+ watts of 100% duty cycle lasers in the 445nm spectrum. I should be able to leave it on until the batteries die.

First I have to give credit to DTR for shipping those modules out so fast. I've killed a few modules developing this.

Secondly AGM for the fine LPM and survival laser for the base host.

Anyway i've developed a water proof laser. Lasers have a limited range penetrating salt water. I find 6" is roughly the range 2.5W laser has. Anything greater then that it is almost a flashlight. So I can either go dual diode or more (but the power requirements goes up exponentially with distance I need to cover) OR I bring the laser to the target subjects.

While testing I noticed that cooling has a profound effect on power output. Notice the ripples on the LPM graphs. The power increase was caused by me blowing on the cooling fins.


Also note this laser is cable of adjusting focus under water. O-ring seals around the focus knob allows me to do this.


The first LPM graph is to show a cold run. 3.1W dropping to 2.8W after 180 seconds. I had to stop the test because of lack of active cooling. If submerged under water it would stay cool. This is with just the survival laser host with G2 lens.

The 2nd graph is the same test but showing you a run after warm up of the laser with G2 lens.

Finally the last graph shows the power output thru my custom water proof housing. Passing thru another plexiglass lens lowers power output by 200mw or so. BUT i'm guessing I can get that power back due to active cooling of the water surrounding the laser.

Anyway enjoy. The first true 2W+ water proof laser

 

[Garoq]

Great job and a nice modification for the application! :beer:

 

[Thejoker301]

Nice work

A 2W-2.5W 445nm waterproof laser is not common at all. This is a Very unique build :beer:

Thanks for sharing ! +1 from me

 

[honeyx]

I just wounder about the heatsink mounted on it. Are the fins made of aluminum? I´m asking because sald water and aluminum is not very good for your corals and other animals.

For saltwater aplications the entire host should be made of V4A steel but no aluminum.

I also don´t think the extra heatsink is necessary when running under water. But well if it´s aluminum and you want to keep it that way, anodize it and clogge the pores afterwards to reduce the corrosion to a minimum.

 

[andyman]

its not icecream! 5 min in salt water isn't gonna harm anything. My SPS corals don't seem to notice the effects. And I don't see any corrossion on the aluminum (i follow up with fresh water baths after every use). I think based on my LPM graphs, cooling fins would definitely give me more power while reducing heat. Plus, when I ordered the heatsinks for my mag light build, I ordered 5 at a time. Didn't know what else to do with these things.

Theres no reason why any laser should have a 50% duty cycle.

 

[honeyx]

No need to use exclamation marks. It´s of course not icecreem but depending on which type of aluminum you have it can include cooper too and this is even worse than aluminum.

About heatsinking under water. I´m running here a watecooled block with 4 diodes. They are giving me 6-7 watts output and the block isn´t much bigger than one of my fingers. So there is way more heat generated at a way smaller size than your host is having.

However. It´s your fishtank and your corals.