“The research team has proposed a mid infrared telemetry and remote sensing method based on the Cassegrain system to address the issue of flexible detection of hydrocarbon gas concentrations over a wide range. This study designed the transmission, reception, and detection modules of the optical system in detail, and adopted a transmissive non spherical collimation structure and coaxial transmission and reception technology to solve the problems of optical signal loss and parallax. The experimental results show that the system can accurately measure the concentration of alkanes within a range of 25-100 meters, with emission and reception efficiencies of up to 86% and 75.8%, respectively. This innovative method not only improves measurement efficiency, but also significantly reduces the risk for measurement personnel, providing a new solution for large-scale rapid detection of hydrocarbon gas concentrations.”