Sub-ppm Methane Detection with Mid-Infrared Slot Waveguides
In November 2023 a scientific group from UiT The Arctic University of Norway and Norwegian University of Science and Technology (NTNU) published in An ACS Transformative Journal (published by American Chemical Society) an article where they described sub-ppm methane detection with mid-infrared slot waveguides using VIGO photodetector.
The text discusses the use of slot waveguides for methane detection and how they can be optimized for different analytes. Authors present a nanophotonic waveguide for methane detection at 3270.4 nm delivering a limit of detection of 0.3 ppm, over 2 orders of magnitude lower than the state-of-the-art of onchip spectroscopy. They achieved this result with a Si slot waveguide. The laser beam was butt-coupled in and out of the waveguide chip and detected on an MCT photovoltaic detector optimized at 3.4 μm with 3 stage thermoelectric cooler (PVI-3TE-3.4) produced by VIGO Photonics. Scientist observed that the sensor response clearly follows the metan concentration change trend, and it correctly quantifies the alternating concentrations. The VIGO detector response to 2 ppm of methan indicates that this concentration approaches the detection limit of the sensor.
Described slot-waveguide sensor with PVI VIGO detector can be used in determining, e.g., landfill gas leaks. Yet, the sensor application goes beyond methane detection it can used in realize a multigas sensor, measure gas fluxes, or provide for isotopespecific gas detection.