Position-Specific Isotope Analysis of Propane by Mid-IR Laser Absorption Spectroscopy.

Intramolecular or position-specific carbon isotope analysis of propane (CH-CH-CH and CH-CH-CH) provides unique insights into its formation mechanism and temperature history. The unambiguous detection of such carbon isotopic distributions with currently established methods is challenging due to the complexity of the technique and the tedious sample preparation. We present a direct and nondestructive analytical technique to quantify the two singly substituted, terminal (C) and central (C), propane isotopomers, based on quantum cascade laser absorption spectroscopy.

Quantum cascade laser absorption spectrometer with a low temperature multipass cell for precision clumped CO measurement.

We present a quantum cascade laser-based absorption spectrometer deploying a compact (145 mL volume) segmented circular multipass cell (SC-MPC) with 6 m optical path length. This SC-MPC is embedded into an effective cooling system to facilitate operation at cryogenic temperatures. For CO, the sample is cooled to 153 K, i.

High-resolution and gapless dual comb spectroscopy with current-tuned quantum cascade lasers.

We present gapless, high-resolution absorption and dispersion spectra obtained with quantum cascade laser frequency combs covering 55 cm. Using phase-sensitive dual comb design, the comb lines are gradually swept over 10 GHz, corresponding to the free spectral range of the laser devices, by applying a current modulation. We show that with interleaving the spectral point spacing is reduced by more than four orders of magnitude over the full spectral span of the frequency comb.