Figure 1.

Principle and schematic of the MIR PA CO₂ monitoring. (a) Concept of the PA system integrated with an H₂-filled ARHCF based MIR Raman laser. (b) Experimental setup, primarily consisting of a pump laser, H₂-filled ARHCF, PA cell, a power meter to record the optical power of the laser, a LIA and a dynamic N₂/CO₂ gas-flow configuration. (c) The spectrum of the pump and generated laser overlaid on top of the simulated absorbance spectrum of CO₂. The right axis shows the simulated absorbance spectrum of CO₂. (d) Pulse profile of the Raman laser; Inset is the measured beam profile in the MIR. (e) Measured PA intensity as a function of the laser pulse energy at two different CO₂ concentrations (500 ppmv and 100 ppmv). Shaded regions correspond to the 95% confidence band for every case.