Methane Sensing via Unbalanced Nonlinear Interferometry using a CMOS Camera

TL;DR

This paper introduces a high-sensitivity, low-cost methane sensing technique using a nonlinear interferometer with a CMOS camera, enabling rapid detection of methane concentrations with high precision and potential for real-world applications.

Contribution

The work demonstrates a novel methane sensing method leveraging stimulated parametric down-conversion and CMOS imaging, enhancing sensitivity, speed, and cost-effectiveness over existing techniques.

Findings

Achieved high-precision methane absorption spectra detection.

Enabled long-distance and low-concentration methane sensing.

Utilized CMOS camera for fast, efficient spatial fringe capture.

Abstract

Here we present a high-sensitivity, rapid, and low-cost method for methane sensing based on a nonlinear interferometer. This method utilizes signal photons generated by stimulated parametric down-conversion (ST-PDC), enabling the use of a silicon detector to capture high-precision methane absorption spectra in the mid-infrared region. By controlling the system loss, we achieve more significant changes in visibility, thereby increasing sensitivity. The methane concentration within a gas cell is determined accurately. In addition, ST-PDC enables long-distance sensing and the capability to measure low ambient methane concentrations in the real world. A low-cost CMOS camera is employed to capture spatial interference fringes, ensuring fast and efficient detection.