Laser Safety

I bring up laser pointers in particular here because laser safety is often an ignored topic especially when it comes to laser pointers. Many laser pointer owners have received them as gifts, purchased them inexpensively online, or were just given one by someone who got bored with it. There is just something about that perfect beam of light, whatever color it may be, that is completely captivating. The first impulse is to point it at something... anything! There is no harm in doing that, right? Well, maybe yes and maybe no... it's best to put some thought into that answer unless there is an actual legitimate purpose in mind, like actually using it (a low powered version) for pointing at the screen during a presentation, or briefly pointing out the location of an astronomical observation to a group of junior astronomers, etc (green works best for this in my opinion).

The earliest laser pointers used to be pretty low power and generally the chance of accidentally causing any physical damage to an eye was relatively low unless it was pointed into an open eye for more than just an instant. Human or animal instinct reflex action being what it is in normal circumstances, the eye quickly closes pretty much automatically before any lasting damage is done by a legal low power laser pointer (below 5mW in the USA). There is certainly no danger of burning skin or igniting something with such a low power laser.

But later, as solid state lasers became more common and MUCH less expensive, one could obtain pretty much any color and power laser pointer online and here is where the real problems began. People began to purchase laser pointers just for fun and some of those people were using them in unwise ways. A laser, like a gun, is only as dangerous as the person using it. These days one can easily buy a potentially very dangerous laser pointer online for quite a bit less that the original low power (legally safe) laser pointers cost back in the day. Certain sellers would (and still do) manufacture them by the thousands and ship them cheap pretty much anywhere in the world that there is someone interested in having one.

As these inexpensive lasers began showing up there were some people (not too many fortunately) who thought it was great fun, either through ignorance or malintent, to point them at aircraft and see if they could hit the thing with the beam. Well, as you might have heard on the news back then, the effect a laser has on the pilot's eyes in a dark cockpit is at the very least temporarily blinding and the pilot can no longer clearly see his instrument displays needed to safely fly the aircraft. Lawmakers quickly crafted laws to deal with this problem and it subsided to some degree, although once in a while someone tries it still. This is just one example of a dangerous use of a laser pointer. I've also heard of at least one instance where someone (who really knew better) had a high power gas laser pointing out of his house and would use a mirror to direct the beam at passing aircraft, so it was not always just laser pointer owners doing this. Of course there are other ways to abuse a laser but enough said for now.

There is another unseen problem with some of the cheaper various color laser pointers that are easily obtainable from many sources... these are made cheaply to be sold cheaply and this sometimes can result in unwanted unseen laser wavelengths emitting along with the intended lower power visible light wavelength. The laser pointers that can have this problem are called DPSS (Diode-Pumped Solid-State) lasers and include the popular green (and several other colors) that require extra optical components inside them that convert a longer invisible wavelength laser's output into the desired green (or other) wavelength. This longer wavelength is in the infrared (IR) range that is above the visible spectrum of light. So, if the internal laser pointer optics are not up to the quality (both material and alignment) they should be, some of the IR laser energy can be emitted as an invisible part of the beam. You might not think that would be a problem except that the IR laser needs to be much higher power to net the desired lower powered visible color at the output side of the optical components. So what happens, if the optics don't block the IR light from escaping like they should, is the actual power output of the laser pointer is much higher than what it is specified to be (at the visible color). This give a false sense of 'safety', the user thinking no harm can befall anyone who he (foolishly) points the laser at, when in actual fact the eye will not react to the higher power invisible IR light (that is probably burning his retina) until it is too late.

So what all this comes down to is that laser pointers (as well as other laser forms) need to be handled SAFELY from the start, just like someone should be handling a gun. Some sellers do have laser safety statements on their websites but not all of them. So depending on where a laser pointer or module is purchased the buyer may or may not see the needed warnings. If they do see them and choose to ignore them then it's on them, but I believe the sellers who do not include the warnings on their websites and in the packages they ship to buyers are wrong for not doing so.

Of course laser safety applies to all versions and classes of lasers and laser safety also applies to yourself. That being said, if you are using lasers in your hobby endeavors you should invest in laser safety glasses or goggles especially if you will be using higher power lasers in you lab. Different glasses work with different wavelengths so you may eventually need several pair to keep your eyeballs safe. Be aware also that there are sellers who make untrue claims about the quality of their laser goggles/glasses, so be sure to do your due diligence in checking them out. There is a laser safety poster I've seen which states "Do not look into laser beam with remaining eye"... a comic statement with a serious message.

Now to some safety tips and web-links - Some of this is basic, some is very in-depth.