The GE Energy controls lab in Niskayuna used to be the home of some laser gear. They kept the sign (presumably to scare off visitors).
Lidar imaging has been around for almost as long as the technology it’s based on, the laser. But unlike its more famous cousin, radar, it was mostly used for research purposes. The reason scientists know so much about the density of aerosols in the upper atmosphere is largely due to shooting powerful lasers into the atmosphere and examining the return signal. That sums up the key difference between lidar and radar: lidar operates with a shorter wavelength so it can, in principle, detect and (sometimes) image smaller objects, like aerosol particles.
This difference has now been given a spectacular demonstration, with researchers imaging the profile of an air rifle bullet in flight with a resolution of about one micrometer (an air rifle bullet is about 5mm long). While air rifles have a rather low muzzle velocity, the researchers could have imaged the bullet from a firearm with a very high muzzle velocity and still had a resolution of about 10 micrometers.
Two lasers that are not quite twins
Old-fashioned lidar systems (and even newer lidar ones) work on the tried-and-true principle of time of flight. Basically, you send out a pulse of light, and record the time it takes to receive an echo. This is a pretty simple system, provided you don’t want very good distance accuracy.
Read 20 remaining paragraphs | Comments
Source: Ars Technica – Lidar system images bullet in flight