Abstract
The multi-pass optical cell is an important tool for high-sensitive laser absorption spectroscopy. For portable emission measurement systems (PEMS), which are useful for on-board measurements of trace-gas emitted from automobiles, a compact design is essential. Therefore, we have constructed a compact multi-pass optical cell based on a pair of cylindrical mirrors. To investigate the performance of the measurements system using the new cell, such as stability and response, 2f wavelength modulation spectroscopy measurements of molecular CO_2 were performed. We also demonstrated the continuous measurements of CO_2 in automobile exhaust and ambient air.
