Abstract

A real-time, nondestructive mid-infrared (mid-IR) platform was proposed for isotopic methane detection. The measurement system consisted of a tunable mid-IR laser, a miniaturized gas chamber, and a mid-IR signal receiver. The isotope ratio of the $^{12}{{\rm{CH}}_4}/^{13}{{\rm{CH}}_4}$ was identified by measuring the mid-IR spectrum at $\lambda = {{3}.\rm{2 {-} 3}.{5}}\;\unicode{x00B5}{\rm m}$. In-situ $^{12}{{\rm{CH}}_4}/^{13}{{\rm{CH}}_4}$ monitoring was then achieved by tracing the characteristic mid-IR absorption peaks assigned to the $^{12}{{\rm{CH}}_4}$ at $\lambda = {3.328}\;\unicode{x00B5}{\rm m}$ and $^{13}{{\rm{CH}}_4}$ at $\lambda = {3.340}\;\unicode{x00B5}{\rm m}$. The real-time methane isotope analysis can be applied to environmental monitoring and petroleum industries.

© 2020 Optical Society of America

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