DESC0025001

Statement of the Problem Enhanced weathering (EW) is a promising method to remove carbon from the soil and mitigate the effects of global warming. EW amends soils (mainly agricultural and forestry soils) with crushed silicate rocks. One of the principal barriers to wide spread implementation of EW is accurate field verification of CO2 removal. General Statement of How this Problem or Situation is Being Addressed In this SBIR program, Amethyst Research proposes to develop and deliver a rugged, compact, low power, low cost, ultra high sensitivity CO2 sensor that can be used for subsurface and above ground measurement. The CO2 monitoring sensor will be small, have a high sensitivity, a high resolution, and be low cost so multiple sensors can be placed throughout the surface and subsurface area to be monitored. The individual CO2 sensors will be based on a novel infrared resonant cavity photodetector that can be tuned to detect only selected wavelengths of light. This high-performance photodetector will then be coupled with a simple LED based infrared light source to measure CO2 with high accuracy and sensitivity What is being done in Phase I In the Phase I program Amethyst Research will develop and optimize the resonant cavity infrared detector optimized to detect light in and around 4.25 ?m where the 12CO2 absorption band is strong and there is minimal interference from other gases. The proposed resonant cavity detector design is a novel versatile design that incorporates an optical filter monolithically onto the detector so an inexpensive light source can be used to measure the CO2 light absorption (concentration) at the absorption wavelength. The high performance photodetector and gas sensor will be laboratory tested to demonstrate CO2 measurement that is sensitive to ppm changes in gas concentration Commercial Application and Other Benefits: Amethyst is developing a low noise high sensitivity mid infrared resonant cavity detector for use in CO2 monitoring. This technology can be translated to other applications including monitoring of other gases as well as IR imagining and IR tomography.