DIY laser hair removal.

[VDX]

... here's a video showing the "shooting" and "cooking" of hairs in slo-mo: https://www.youtube.com/watch?v=S20-1_XqVPM

With only minimal changed parameters the skin will be evaporated or cooked too - so not really suited for offering this on semipro basis ...

Viktor

[Finale]

Jokes aside I think the parts needed to build such a hair removal system is probably available on eBay and I wouldn't be surprised if it would be in the sub $100 region to build something like this, the brick wall to make it would probably be that all the knowledge is trade secrets and on top of that as others have pointed out even if you somehow had all the knowledge you needed to make it there's just too much that can go wrong and you shouldn't risk burning or causing skin cancer to yourself or someone else.

And the last reason why I think you shouldn't bother and which is actually good news for the OP if he/she was thinking about this as they couldn't afford professional laser hair removal treatments is, well, branded home electrolysis kits cost around $50 and they really are permanent.
Yes, it's more painful but it's permanent and if you tune the power to your skin sensitivity you won't end up with tiny scars.
How do I know this? Well i

[planters]

Has anybody tried removing hair at home via laser?
Or happen to how if this could done on the cheap by building your own hair removal machine.
Getting laser done at a spa costs hundreds of dollars per treatment.

I have owned, operated and sold lasers that were built expressly for this purpose.

The concept is simple, but the execution is difficult. You can buy a knife on eBay, even a scalpel, but taking the next step and performing an appendectomy is where it breaks down. To give you some perspective, the laser that was needed to remove blond hair (difficult) was not the same as the laser that would work well on dark hair. The pigmentation level of the skin makes a large difference in the ability of the skin to withstand a given fluence. You could burn one individual with a laser energy that was ineffective at removing the hair of another.

I wouldn't be surprised if it would be in the sub $100 region to build something like this

I don't think so. The lasers have to be pretty powerful and the control has to be pretty good. There are a few of us here that could construct a system, given a much larger budget, but we are a pretty unusual group. Yet, I haven't even begun to discuss the legal tangles involved with this and... YOU DO NOT WANT TO TRANSGRESS THESE LAWS. This is not like skirting the regulations that apply to laser projectors in clubs. They will nail you for this.

good news for the OP if he/she was thinking about this as they couldn't afford professional laser hair removal treatments is, well, branded home electrolysis kits cost around $50 and they really are permanent.

This is true. Even if some of the literature suggests this is not permanent, it most definitely lasts longer and laser hair removal is far from painless.

[Finale]

The concept is simple, but the execution is difficult. You can buy a knife on eBay, even a scalpel, but taking the next step and performing an appendectomy is where it breaks down.

This is pretty much what I wanted to say but worded better.

This is true. Even if some of the literature suggests this is not permanent, it most definitely lasts longer and laser hair removal is far from painless.

True.
I can only give personal experience. If the pin is not inserted properly (deep enough or in the correct hole) it might weaken the hair follicle and cause the hair to fall but not kill the follicle to prevent future hair growth. But once the hair follicle is properly targeted and burned it's dead.
I don't know what people who disagree with this being permanent say, could be the body creating new hair follicles for some reason in the same tissue area.
From what I know about laser hair removal is that the laser burns the hair outside and inside the skin which might indirectly damage the follicle from the generated heat, but it doesn't actually target the follicle itself, so it weakens the follicle but doesn't kill it most of the time. Or so I've been told.

[planters]

but it doesn't actually target the follicle itself

The target is melanin. At its base the hair begins to accumulate this modified protein and will absorb the light which in turn heats and potentially damages or kills the cells that generate the hair. Both electrolysis and laser do their work through heat deposition. Electrolysis is independent of melanin content and is often the only option for red or blond hair unless the most expensive lasers are available. Coherent's near IR, direct diodes work quite well on dark hair and so the optimal situation is on light skinned individuals with dark hair.

Dye lasers and green light lasers target hemoglobin.

Q switched lasers target the metallic components in tattoos that fracture into particles that are then small enough that the body's lymphatic system is able to clear them.

CO2, holmium and erbium lasers target water.

Quantum dot lasers don't survive vigorous pumping and don't work well...damn!

[VDX]

... I'm actually thinking about fibercoupled UV-lasers with shortest possible wavelengths and only some ten to hundred Milliwatts of power - use the fiber in the same manor as the electrolysis electrode = insert it into the folicle hole and "disintegrate" the hair root zone ...

Viktor

[swamidog]

... I'm actually thinking about fibercoupled UV-lasers with shortest possible wavelengths and only some ten to hundred Milliwatts of power - use the fiber in the same manor as the electrolysis electrode = insert it into the folicle hole and "disintegrate" the hair root zone ...

Viktor

i don't want a high concentration of uv injected into my skin. may be safe, but i'd rather not find out the hard way.

[planters]

This would work, but why do it? Once you loose the advantage of many hairs treated at once then the electrolysis approach is cheaper and at least as effective.

[Finale]

The target is melanin. At its base the hair begins to accumulate this modified protein and will absorb the light which in turn heats and potentially damages or kills the cells that generate the hair.

I always thought the cells of the follicle which generate the hair don't add color to it (that is why they are white at the very base) and melanocyte cells later add the color to the hair cells at a higher layer inside the skin. But biology has never been my strong side.

[VDX]

This would work, but why do it? Once you loose the advantage of many hairs treated at once then the electrolysis approach is cheaper and at least as effective.

... electrolysis seems to hurt more than only the hair roots, as the high current path is running through the nearby nerves and surrounding tissues ... and too is prone for wrong settings and "undefined" results.

With short UV wavelengths (low penetration depth) and pointing cone of the fiber tip the specific "damaged area" can be set very precise and much sharper localized ...

Viktor