Laser device detects poisonous gas in half a second

Researchers at the University of Michigan have created a device to detect poisonous and dangerous gases in less than half a second (some of which cause explosions).

The laser-based method could be used as a security device at airports and the monitoring of pollutants or toxins in the environment. The findings of physicists are based on a method developed last year, but this old methodology detects the gases in about four or five minutes while the current device uses three lasers to significantly reduce detection time. Up-to-date research undoubtedly changes the landscape so far in this area.

Steven Cundiff, principal investigator, said: “The great advantage of the new device we’ve created is that it can detect in a much simpler, faster and more dynamic manner all those gases that until now required a time consuming process. This is particularly critical for the practical application of the device. If you’re watching the environment, you have to do it logically quickly, due to fluctuations in the environment. You do not want to wait five minutes to find out that there is poisonous gas in the atmosphere. ”

The gases have certain wavelengths that can be read using laser. The researchers used a method called “multidimensional coherent spectroscopy” or MDCS. MDCS uses ultrashort laser pulses to read these wavelengths, such as barcodes. The specific wavelength of a gas determines the kind of gas that is.

Many gases have a very rich spectrum at certain wavelengths or colors of light – although “colors” can actually lie in infrared radiation, so it is not visible to the human eye. The spectra help and make it easy to identify the gases. But this becomes difficult when scientists try to identify the gases in a mixture. In the past, scientists relied on controlling their measurements in a molecule list, a process that requires high-performance computers and a significant amount of time.

The previous methodology used MDCS by another method called dual-comb spectroscopy to reduce detection time to four or five minutes. Frequency bundles are laser sources that produce spectra composed of uniform steep lines. These lines are used as rules for measuring the spectral characteristics of atoms and molecules, by precisely identifying them. In double-beam spectroscopy, lasers send light pulses into different patterns to quickly detect gas imprints.

Now, Cundiff and his team have added an additional laser detection layer to reduce the detection time even further, using a method called tri-comb spectroscopy. This is the first time that triple beam spectroscopy has been shown to work perfectly in this aspect of the subject, and indeed very dynamic.

The research team added a third laser and linked them through a software programmable to program the patterns of light pulses emitted by the device. The lasers are synchronized with each other in order to produce specific pulses so they can scan and recognize the gases.

To understand how the device works: Two lasers send light pulses in the same direction, which are combined along the path in a beam. This beam passes through a gas vapor and after the beam passes through the steam, it is combined with the beam by a third laser. Then the final beam of the detector measures the spectra of the gas mixture and determines the formula.

Cundiff hopes to apply the device to existing fiber optic technology and to control laser pulses with software. In this way, the software can be customized to specific environments.