To prevent light from reaching the detector from sources other than light
transmitted through the head, the experiment was performed in a light-tight
enclosure that surrounded the head. The enclosure was built using black
foamboard and covered with two layers of black cloth and a laser safety
curtain.
https://spectrum.ieee.org/media-library/a-3d-illustration-sh...
Non-invasively. No "below threshold of detection". Beyond anything our scientists say is possible.
We're just not advanced enough as a species to do it yet.
We need to keep pushing these boundaries.
Sunlight contains copious amounts of 800-nm light, so this is probably completely non-hazardous.
1.2 watts over your entire head is fine.
1.2 watts in a 800nm-diameter cylindrical path is "for some reason we decided to make the outer few millimetres of your skin explode, but we had to be in contact with your skin to manage that because that power density of laser would have ionised the air before it reached you".
milliams•1h ago