17 Jun 2002
German scientists have joined forces to develop infrared gas sensors based on quantum cascade lasers.
A group of Germany-based research institutes has launched a project to develop infrared gas sensors based on quantum cascade (QC) lasers. Called QUANKAS, the group comprises the Fraunhofer Institutes for Physical Measurement Techniques (IPM) and Applied Solid State Physics, and the Universities of Würzburg and Darmstadt.
"We have decided to launch this project because we are very much involved in spectroscopic measurements and would like to push the development of these devices," said Thomas Beyer of the Fraunhofer Institute IPM. "I see a big advantage in this collaboration."
QC lasers were pioneered by research laboratories including Bell Labs, US, and Switzerland-based AlpesLasers several years ago. The lasers are based on semiconductor layers, sometimes only atoms thick, that combine to create a series of quantum wells. As the electrons in a QC laser pass through the quantum wells they emit a "cascade" of infrared photons.
Unlike other infrared lasers, QC lasers are ideal for gas sensors because they operate at room temperature. Laser manufacturers can also vary infrared wavelength emissions by altering the thickness and spacing of the semiconductor layers.
Currently investigating InP- and GaAs-based lasers, QUANKAS hopes that its work will pave the way to compact, user-friendly measurement systems.
"Our laser spectrometers measure gases that absorb infrared light, such as ammonia, nitrogen, carbon monoxide and hydrocarbons," said Beyer. "We are at the beginning [of the work], but I'm confident that we will reach room-temperature pulsed-operation."
In time the group plans to patent its developments for industrial use and expects to see a fully-integrated sensor by the beginning of 2004.
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