It's a very sensitive detection technique that uses some cool properties of light. We used it 20+ years ago in grad school (they were very expensive machines that were extremely hard to master; everything from calibration to routine operation was significantly more challenging than most devices I worked with) and I think it has quite a history before that. Never heard of it being used for rapid detection in a public environment; my experience is that things that work in a lab setting often don't externally unless somebody comes up with a good technology improvement (think vacuum tubes -> transistors -> small radios).