However, when there are many 865 nm lidars around, each one gets focused to a different spot in your retina, so it is not any more likely to cause damage than a single lidar. Thanks to the low power of the Ouster lidar, it is Class 1 eye-safe at any distance.
If there were a hundred high-power 1550 nm lidars all pointed at the surface of your eyeball, however, I wonder if it would be more likely to cause damage?
I wonder how much we have to blame ITAR restrictions on >1555nm lasers for things like this not being more eye-safe on a by-wavelength basis.
I tried looking up information about this (restriction details, otherwise feasible uses beyond that wavelength, etc) but it's hard for an outsider to quickly make sense of. Any chance you could elaborate?
The main section on lasers starts on page 47. The rules are very complicated. See 6A995 d and f.
Lasers are also covered in other sections like 6A205. (I'm amused by Raman shifters being covered-- they're literally just pressurized tubes with hydrogen and mirrors at the end-- I can't imagine anyone qualified to use one couldn't have one fabricated pretty much anywhere).
I'm concerned once these become more prevalent on all cars or whatever else we stick these on. Curious if there's any studies on if it affects our eyes in anyway.
Lidar uses very short pulses and very low power and is very safe even en masse.
Due to optical aberration wavelengths outside of visible range don't get focused the same way as visible light. This means that the energy is spread over larger area.
Also, both UV and IR light is absorbed in a different way. UV tends to be absorbed much faster than visible light so that little of it reaches the retina while for IR opposite is true, the eye is more translucent to IR and only a portion of it is absorbed at retina and a lot of it tends to pass through it.
What it means is that, while a source of visible light is very well focused on the retina and absorbed in very small volume of retina cells, UV and IR are spread over larger area and then large part of it is absorbed somewhere else.
Still it doesn't mean IR or UV beams aren't dangerous. It is just that you can't directly compare beams by their power.
The way I understand it the main danger is that, since people may not see the IR or UV beam very well, there might be no involuntary response to close the eye.
Thank you to all involved.
If anyone can point me to the generalized best studies for safety margins and laser energy, please post links -- it's pretty relevant to a lot of AR designs to use laser projectors, and it is of course relevant to the lidar self driving cars at question.
If it's not visible I'm not sure that your eye will react quickly enough to prevent damage.
Unless those heat lamps that also produce visible light damage the eye, I don't see how 865nm lidar could do it if the power is low.
I’d be absolutely shocked if biological systems were somehow different.