Comment by tzs

The eye safety issue with laser mosquito zapping could be addressed with multiple beams.

Say you need to deliver at least M joules of energy at the wavelength of the laser to the mosquito over at most T seconds in order to kill it, and suppose and eyes must receive less than E joules of energy at the wavelength over that same timeframe to not be damaged.

Encircle the area you want to protect with at least M/E lasers each individually each with low enough output power to not damage an eye if they hit is directly. Control all these lasers with a common controller which picks out a target and fires all the lasers at it simultaneously.

The target gets hit with all the lasers receiving a fatal rapid influx in energy. Anyplace else in the area that gets hit by any beams that miss the target should only get hit by one and so be safe.

Add a suitable safety margin by increasing the number of lasers and decreasing their individual power so that even if a person or animal gets a direct hit from one beam plus reflections from a couple more they will be safe.

That should be safe for almost all normal rooms. Train the installers to refuse to install in places with a lot of curved reflective surfaces, such as mirror coated elliptical room where a miss trying to zap a mosquito at one focus could be bad news for a human at the other focus.