It used a micropulse of IR laser. Your eye couldn't see it, nor focus it properly. However, it had just enough power to overheat and damage the mosquito wings.
I believe the issue was with the targeting. It could don't, but not cheap enough for the mass deployment they intended. Mosquito nets were far more effective, once cost was accounted for.
A laser strong enough to shoot a mosquito down will also be strong enough to cause instant permanent blindness. Would you really want to be in the same room as that thing?
As long as I'm not looking at it I'd feel more comfortable with it that being surrounded by mosquitoes. Would you rather be surrounded by mosquitoes than be in the same room as that thing?
Doubt anything like that id available for sale. He took the radar from a car, probably needed some serious tweaking to get it to track smaller objects and ignore larger ones.
If you have any military connections, get your hands on a AN/APG-81 from an F-35 and cook all the mosquitos in the room. Get any pets or food out first, of course.
I don't doubt a laser could fry a mosquito; but could a mosquito actually be seen on radar? I would think LIDAR would be better at detecting such a small thing, and even then...