14 DAY TRIAL // Over the past few years, the number of monitoring, imaging and detection technologies based on lasers have increased considerably. Princeton University experts are now proposing a new one, that could help bomb squads detect explosive devices, or climate scientists measure pollutant levels in the air.
Engineers at the university say that their new device could also be used to measure airborne environmentally-damaging chemicals, aerosols, as well as greenhouse gas concentrations. Keeping an eye on these factors could result in better climate models for Earth's future.
Unlike any other remote laser-sensing method, the new one does not rely on sending out a laser signal, and then analyzing the reflections or scatterings that return to the light source. The instrument is in fact observing an entirely new laser beam.
The latter is obtained by exciting oxygen atoms in the air, the team explains. “We are able to send a laser pulse out and get another pulse back from the air itself,” researcher Richard Miles explains.
“The returning beam interacts with the molecules in the air and carries their finger prints,” says the Princeton scientist, who is the leader of the research effort. He is also the coauthor of a new study detailing how the device operates.
The investigators goes on to say that the “air laser” the new device is analyzing is a much more potent tool for analysis than anything else available to other laser-based monitoring devices in the past.
This technology allows experts to measure even trace amounts of specific chemicals in the air, including hazardous substances in bombs, chemical spills, pollutants and so on, Science Daily reports.
“In general, when you want to determine if there are contaminants in the air you need to collect a sample of that air and test it. But with remote sensing you don't need to do that,” Miles explains.
“If there's a bomb buried on the road ahead of you, you'd like to detect it by sampling the surrounding air, much like bomb-sniffing dogs can do, except from far away,” he goes on to explains.
“That way you're out of the blast zone if it explodes. It's the same thing with hazardous gases – you don't want to be there yourself. Greenhouse gases and pollutants are up in the atmosphere, so sampling is difficult,” the researcher argues.
Details about the new device were published in the January 28 issue of the top journal Science. The effort was sponsored through the US Office of Naval Research (ONR) Sciences Addressing Asymmetric Explosive Threats basic research program.
“We'd like to be able to detect contaminants that are below a few parts per billion of the air molecules. That's an incredibly small number of molecules to find among the huge number of benign air molecules,” the team leader explains.