Low-power photonic sensor network for soil carbon sequestration monitoring
Miniature, wireless photonic sensors using optical absorption spectroscopy to monitor soil microbial activity and carbon sequestration by measuring CO2, CH4, and O2 concentration ratios. Designed for deployment in standard 4-inch monitoring wells, these calibration-free sensors address drift and cross-sensitivity limitations of existing low-cost gas sensors.
Overview
This technology offers a network of miniature, low-power photonic sensors designed to monitor carbon sequestration in soil by tracking microbial activity through gas concentration measurements. The sensors measure CO2, CH4, and O2 levels, using concentration ratios to distinguish between oxidative and reductive environments, CO2 dissolution, and influx of exogenous gases. By leveraging the natural mobility of gases within the vadose zone, the network avoids the outlier measurements that plague localized sampling near sequestration hot spots or inactive zones. The solution addresses a critical gap in agricultural and environmental soil monitoring, where existing low-cost sensors exhibit excessive drift and CH4 sensors suffer from cross-sensitivity to other gases.
Technical specifications
- Optical absorption spectroscopy using inexpensive, reliable diode lasers similar to those used in fiber optic telecommunications
- Calibration-free gas analysis based on first principles, free of cross-interference from other soil or atmospheric gases, and self-calibrating
- Measures CO2, CH4, and O2 (O2 sensing to be added in a later phase)
- Sensors designed for deployment in standard 4-inch monitoring wells
- Wireless linking of sensor nodes for distributed network monitoring
- 3D-printed plastic optomechanical components for low-cost, reproducible manufacturing
- Laser control electronics modified for compatibility with a simple microcontroller
- Validated against a commercial gas analyzer serving as a standard for atmospheric and soil gas measurements
- Performance targets include sensitivity, accuracy, repeatability, dynamic range, cross-sensitivity to moisture, and temperature stability
Technology readiness level
This project is at the proof-of-principle stage. The underlying optical absorption spectroscopy technique has been established for over 30 years, with prior implementations by the proposing team. The current effort focuses on demonstrating the approach with miniature commercial diode lasers for CO2 and CH4 detection, with O2 sensing planned for future development. Validation will benchmark sensor performance against an established commercial gas analyzer. Upon successful validation, the technology is positioned for further development toward distributed field deployment for agricultural soil monitoring, carbon credit verification, and environmental research applications.
About Mesa Photonics LLC
Mesa Photonics, LLC develops and manufactures advanced scientific test and measurement equipment, specializing in real-time ultrafast laser pulse measurement systems. Their core technology, Frequency-Resolved Optical Gating (FROG), is utilized in products like the FROGscan line to characterize laser pulses, measure chirp, and facilitate dispersion compensation for pulses ranging from 5 fs to 30 ps. Beyond ultrafast characterization, the company develops instruments for optical absorption spectroscopy, aerosol characterization, and high-precision optical delay lines. Their systems are designed to be versatile and field-upgradeable, offering reconfigurable wavelength ranges and high dynamic range detection for researchers and industrial users.
These measurement solutions are essential for researchers tweaking laser systems, conducting pump-probe experiments, or performing complex pulse analysis. Mesa Photonics serves global scientific communities, including those in atmospheric science, petrochemical monitoring, and biomedical imaging, by providing tools that solve technical challenges in light-matter interaction and gas sensing. The company’s staff includes experienced scientists with expertise in chemical kinetics, laser spectroscopy, and instrumentation design, holding multiple patents in the field. They maintain operations in Santa Fe, New Mexico, and have historically engaged with research programs, including the SBIR portfolio, to advance optical sensing and detection technologies.
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