The highly experienced laser professional is actually also one of the better known Laser Hobbyists and has been so since he was a wet behind the ears newbie long ago.
He's terrified by what he sees on Youtube, and in person, having been out doing very safe, carefully controlled laser shows and having idiots illuminate the Laserist or Artist (often himslf) with pointers that have a very high irradiance that are well beyond by a factor or 100 or more over what he considers to be safe in terms of beam product. Note I said product, a nonstandard term consisting of the diameter, divergence, peak power, continuous wave power, a measurement known as M Squared, distance, the size of his or other's pupil, and if the beam is scanned, Q-Switched, Mode Locked, up collimated etc. I have a very good model in my head of what it takes to fatigue the eye, bleach the pigment, or actually do damage. I've also been hit while in a friends light plane, and by teenagers on a bridge when driving. High power laser pointers are evil. OZ's rules of approved devices only and customs confiscation are great.
When I was in my late teens, a female friend from high school, whose parents were stockholders of a marine life park company, got me the "dream job" on what in 1990s Dollars was a Three Million Dollar nightly attraction using lasers, pyro, water-skiers, fast boats, 70 mm water-screen rear projection , water skiers, dancers, etc. I was working on what then was the state of the art in visible lasers at the park, and learned the hard way about the real hazard, human nature. I had the system idling and detuned at a vary low power. I had a lock-out tag out on the main key switch some 1500 feet away. An Idiot, ie slightly older college student, came in and pulled off the Tagout, ignored the note taped over the key, and booted the system.
My "safe", by the book, setup turned into a nightmare as actuators moved on the beam-table with no warning, and I found myself with a tiny burn in the peripheral. Like most people who gain eye damage in the workplace, I went though hell as my brain adapted the visual cortex to try to work around the damage. It will try, but watching your vision try to remap the neural net in real time for the few weeks is NOT fun. Not too bad after all, it missed the Fovea and the Macula, just for the rest of my life I've had to look more then most when walking / driving at Crosspoint's. I wont see the truck that hits me, is sort of the true joke, and over decades it has cleaned up a bit.
Having three universities , a government depository library, and a medical school near by, I spent a lot of time learning about laser safety. I'll spare you the details, but there are a bunch of laser professionals who have became expert in radiation safety due to preventable or unpreventablk eye injuries. Of The best in the word who is still living, got his burn while looking down the bore of Argon Ion Laser that had a malfunctioing start timer.
To counter that, there are carefully designed and highly regulated laser based projectors that legally able to audience scan, and after a really long moratorium on outdoor laser shows, due to an "incident", I have also fought for your right to legally own lasers in the background. I've said that to assure you I'm not some bitter jerk who had a whoopsie and never recovered, far from it.
So here's what I know, at the risk of your continuing down the path based on giving you more information. Diode lasers suck at diameter, divergence, beamquality, wavelength statbily, sensitivity to certain kinds of back reflection, and multimode diode lasers do not propagate though fibers worth a damn. Which is why bundles and correcting optics are used. In teh past ten years there have been some breakthroughs, but MOST (Not all) high power diode lasers have a figure of merit (known as M^2) parameter that is horrible, and always above 2 or more.
This means the collimated divergence is huge, the spot size is very large, it takes a far higher power system to achievde what a more expensive different type of laser can do. A factor known as Etendue comes into play.
So large amounts of high power fiber coupled diode laser lasers get dumped into surplus. A large amount of factory rejects due to wavelength problems during manufacturing are out there too. As are some overuns dumped on the market. Very high power diode arrays are out there, and they are all the rage for folks who cannot afford what I refer to as "the Good Stuff". With the FCDL leakage and stray light are huge.
Fiber Lasers are also dumped on the market, subsidized, to capture Dollars into certain countries, but Dave and I would agree that would diverge into a hugely unpopular political discussion fast.
The regulatory agencies have other issues to cover, like industrial, illegal medical laser devices, illegal drugs, etc. Believe it or not US Customs tries hard to catch the illegal imports, but there is little that can be done about the surplus market in the US. The rules have simply not caught up. You can buy a Five Megawatt laser easily, and legally. What you do with it is when the law kicks in. Again, I diverge.
This provides the illusion that high power lasers and uncertified laser cutters are inherently safe.. They are not.
Being one of the early, and premier laser hobbyists had an odd side effect. In the past, I would frequently get calls from Law Enforcement who would track me down on behalf of a physician or institution of higher learning, and patch in a phone call asking what to do after a retinal injury. These calls were often frantic, and the turth is, after administering steroids and a few other drugs, only time will tell on the damage. I would usually patch or link the doctor or victims through to a military hospital who had the US Military center of excellence on laser eye injuries. That asset is no longer available to the public.
So, before you criticize me on my reply, I have pretty good physics and ethics reasons why I am discouraging you.
OH, BTW, in the US, when the insurance code is entered in the database for a laser injury, it goes down coded as "Optical Neuropathy, Unspecified" , so it is difficult to collect data on actual injury rates. Its rare, but much higher then published. Stats say Local, Sate and Federal Governmens only take an interest in injuries when the rate reaches between 1 in 300,000 or 1 in 1,000,000. In fact there is a rough federal rule in the US on what the minimum amount of sick people has to be before Federal research Dollars can go toward a cause. This results in "Orphan" diseases that are horrible, but not addressed, except through sheer determination.
So your trying, in my opinion, to run a horribly inefficient process with the wrong laser, and your expressing a naïve attitude. Your citing, if not clinging videos that show a distinct lack of shielding.
So the rule, if applied, Worldwide, is properly shielded laser is designated Class I (very safe) with a second sticker on it that says do not defeat interlocks and housing (and a few other things).
You can have a Class IV laser marked Class I, and this gives the public the wrong idea in videos on laser use.
And for those who say, go ahead, hurt yourself if you want, but do not harm others, that is poorly thought out, Nearly all of us have loved ones and persons who are dependent on us in one way or the other. Taxes have to rise for covering those who do not die, but live with a debilitating injury resulting in dependence on Social Welfare systems. So...
Sort of Rant, Over. I've typed a few dozen variations over the years in various places, and spoke to this at industry and hobby conferences.
Steve
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