Laser dump for sale

[Laserburns]

I think you can improve you specs, a 90% absorbtion is very low, a flat black surface can do that. Professional beam dumps can have a 99.99% absorbtion. I think yours does much better than 90%, probably above 99%

Yes, probably. I do not have the instruments to check the intensity of the diffuse light returning from the tube, but is very very mild and eye tolerable, i was able to dump a spartan, and while dumped, take off the goggles, without getting any kind of disturb, the room was kinda dark. So, just the beam was visible and a mild diffuse blue, behind the laser on the tripod.

 

[Laserburns]

Cause it can be helpful, at hobby level, this is my personal beamdump design (i had to plan something different, when i needed one, cause i don't have a lathe ..... BTW, this is released under creative common, open-source licenses, free for personal use, not for companies, or whatever it's called that thing )

First take a piece of aluminium rod and cut it diagonally with an angle around 10 degrees or similar, then cut away also a small piece from the back side, so you will end with a shape like in the first draw, and "scratch raw" the surfaces that are exposed to the beam (do it in the sense of the lenght, NOT in the sense of the height, so this reduce the back reflections too)

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With all the respects on your design (why dont you try by yourself?)

I think that a DIRECT laser beam, reacts (as your design) as a bouncing ball, for a percentace of its power, let's say..80%... but when it bounce the first time to any matte surface, i think that it mostly reacts like a "splash of water"..so, from my point of view, that sort of upstears, would not give the efficience that you imagine... IMHO a streight design, or an internal mirror at 90 degress pointing to a second, deep cavity, would be better.

 

[HIMNL9]

With all the respects on your design (why dont you try by yourself?)

I think that a DIRECT laser beam, reacts (as your design) as a bouncing ball, for a percentace of its power, let's say..80%... but when it bounce the first time to any matte surface, i think that it mostly reacts like a "splash of water"..so, from my point of view, that sort of upstears, would not give the efficience that you imagine... IMHO a streight design, or an internal mirror at 90 degress pointing to a second, deep cavity, would be better.

I've made one of them in the past (having no access to lathe, that was the only design that i had the possibility to build "handy" with a certain easyness), and it worked decently, so i just posted the draw for give an idea (not for threadjack your post, i don't sell them )

The inclinated surface don't reflect too much back, cause as you probably know, also matte paint have a certain degree of reflection in the optical angle, so a good part of the beam ends reflected in the back cavity.

I also had planned and designed a much better version, based on the same principle, but the problem for me is always the same (no lathe), so never had the possibility to test it ..... as conceptual idea, i can say you that it may work much better if also the inside of the tube can be "waved", before paint it ..... maybe is enough to thread it inside with a big tap tool ..... as example, same size of the thread track that you have on the tube in your first pic, but INSIDE the tube, instead than outside, will probably take care of another 90% of the scattered reflections from the inside, and improve the efficency also more, and this may be much more easy to do than with a lathe (i mean, same result, but doing that with a lathe is probably much more difficult than do it just threading the tube with a tap tool).

EDIT: i also had a design involving a spherical cavity, but that may probably end in a nightmare for the builder (also if, theorically, the efficence must be almost 100% )

 

[Laserburns]

EDIT: i also had a design involving a spherical cavity, but that may probably end in a nightmare for the builder (also if, theorically, the efficence must be almost 100% )

This is one of the design i made, kinda of crafty, but i really think you get 99,9999% out of it

The black termination, would be a legue of cast iron and black stone.
As long is quite centered, the heat would be properly diffused.

 

[HIMNL9]

^yes, but please note that this setup requires mirrors, and same as they convey the beam in, they can convey the scattered light out.

My original idea for a high power beamdump was starting from an aluminium rod and ending with the one in the attached images (seen from side, it's just a conceptual image, the technical specs are a bit more detailed and the inside "waves" in the front hemisphere are more fine, like, a pair of millimeters) ..... also, the joining between the two parts can also be made with a thread screw, not necessarily with passing screws on the border (the easiest system is the better system, usually ) ..... and all the parts must be heavily black matte anodized, in and out, for high powers (paint, also high temp one, can't resist at too much power) .

It was based on the optical principle of the virtual black body, so the efficence must be good enough, but as you can see, is not easy to obtain the parts with also just a lathe ..... probably someone with a CNC lathe or machine can try to build it, but is not at the level of a hobbyst with a minilathe or hand lathe (i also doubt that with a normal lathe you can obtain a decent spherical profile ..... a CNC machine is mandatory, probably, but here there is none with a similar tool that can work for privates, and companies asks too much also just for the setup, so i never had the possibility to build a prototype.

If someone with a CNC want to try it, they're welcome

 

[Bluefan]

The first reflection is important, A matte surface will reflect in all directions, so a 45 degree tilt in the surface will still reflect back. The beamdumps of CVI (Melles Griot) use a pointy cone as the first surface, works pretty neat.
I have a Laser Precision RkP-575, a thermal power meter that also uses such a cavity to trap the light, this way it has a very good spectral flatness.

 

[HIMNL9]

^ i know ..... mine is a lateral section view of a cylindrical cavity, so the "tip" where the beam hit is, in fact, a cone ..... also, having a curved surface itself, the cone reflect the beam enlarging it, not straight.

It's, basically, the same principle of working of a "virtual black body" (only adapted for trap high power beams, instead that for give you "black" color reference ) ..... the only problem is that, for build one, you need a CNC lathe :cryyy: