Fast Gas Detector Senses Unlimited Industrial Emissions

AUTUM C. PYLANT, NEWS EDITOR, autum.pylant@photonics.com

Combining photonics principles seen in fiber optics — multiplexing to demultiplexing filters and modulation and wavelength tuning — with mid-IR spectroscopic sensing technologies, European scientists are well on their way to producing the world’s fastest gas detector.

Researchers for the MIREGAS — Mid-IR source for Gas Sensing — project have created an adjustable device that uses only one light source, as opposed to several lasers. Professor Pentti Karioja from the VTT Technical Research Center of Finland Ltd. told Photonics Media that using one controllable light source has its benefits.

“The system is simpler and less expensive,” he said. “Moreover, the MIREGAS light source with lower optical coherence compared to a laser will allow for good spectroscopic performance without expensive optical elements to reduce speckle and fringing effects.”

The project is filling a gap, as affordable sources are not available. Conventional gas sensors can cost in excess of €75,000 [about $79,000]. As mentioned by Karioja, their product is less expensive with a manufacturing cost of below €300 [about $317] per unit.

The MIREGAS device can make multiple readings with one filter and pick out poisonous gases from a mixture of emissions to include methane, ethane, butane, propane, CO₂, carbon monoxide, hydrogen sulphide and benzene.

The device is also fast; it’s several thousand times faster than current state-of-the-art gas sensors, detecting dozens of harmful emissions in mere milliseconds.

“A system with short response time can be used for closed-loop control of industrial processes, which is what customers are very much interested in,” said Karioja. “This will improve the quality of the product yield and reduce waste.”

The novel technique combines silicon photonic integrated circuit (PIC) filters and wideband superluminescent diodes (SLED) at 3 µm, a process never seen before. The MIREGAS device promises to be faster, cheaper and have better spectral resolution than what is currently on the market. Furthermore, it has the potential to be programmed to detect an unlimited number of gases, making it very applicable in industrial process and environmental monitoring.

VTT in Finland is coordinating the MIREGAS project with other consortium members in Poland and Norway to include Tampere University of Technology, Vaisala OYJ, the Instytut Technologii Materialow Elektronicznych, Airoptic, Vigo System S.A. and Gassecure AS. The three-year project will be complete at the end of next year.