Light Shows: Are we attacking the audience with lasers?
Well, the short answer is (hopefully) no. But the question is how can we be so sure? After all, these are the same lasers that are used by metal manufacturers to cut steel in record times and by the military as the future of weapons.
Like many things in life, this is a question of degree. Many people have pet cats, but few would take a cougar into their home. The same is true with lasers. At high power and energy densities, lasers can be brutal. They slice metal and vaporize rock. But the same lasers at different parameters are used in non-invasive medical procedures and, yes, for entertainment in light shows.
I want to talk about how we can be certain that light shows are indeed safe for human exposure. The European Union recently established a safety threshold for laser light exposure, called Exposure Limit Values (ELV’s). Somehow it was decided that a laser with power up to X watts is safe to be exposed to for Y seconds. That’s great, but how is a light show operator or engineer supposed to measure this? There are in fact quite a few products that measure laser power and energy. However, these laser power and energy sensors are usually meant to measure a steady (CW) or pulsed laser beam that is constant in its direction. This is not appropriate for a laser show. Could you imagine going to a laser show where they just shined a CW – or even pulsed – laser beam at a screen for 20 minutes? I’d ask for my money back. The beauty of the laser show comes from scanning the laser and splitting it to create all sorts of wild designs and patterns. This is much nicer to watch but much more complex to measure.
Until recently, most laser show staff and safety regulators used traditional laser power meters and photodiode sensors to measure laser show ELV’s. These methods, however, can be off by a factor of 10. This means it’s possible to pass safety standards while the laser exposure is really 10 times the maximum allowed ELV! Read how a health and safety practitioner from the UK talks about Ophir’s unique solution for measuring laser show emissions
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