Linear probing of molecules at micrometric distances from a surface with sub-Doppler frequency resolution

Abstract

We report on precision spectroscopy of sub-wavelength confined molecular gases. This was obtained by rovibrational selective reflection of $\mathrm{N}{\mathrm{H}}_3$ and $\mathrm{S}{\mathrm{F}}_6$ gases using a quantum cascade laser at $\lambda \approx 10.6\mu m$. Our technique probes molecules at micrometric distances ($\approx \lambda /2\pi$) from the window of a macroscopic cell with sub-MHz resolution, allowing molecule-surface interaction spectroscopy. We exploit the linearity and high-resolution of our technique to gain novel spectroscopic information on the $\mathrm{S}{\mathrm{F}}_6$ greenhouse gas, useful for enriching molecular databases. The natural extension of our work to thin-cells will allow compact frequency references and improved measurements of the Casimir-Polder interaction with molecules.

accepted for publication in Physical Review Letters

References in corpus (8)

• Quantum cascade laser frequency stabilisation at the sub-Hz level
• Casimir-Polder forces in the presence of thermally excited surface modes
• A new experiment to test parity symmetry in cold chiral molecules using vibrational spectroscopy
• A widely tunable 10-$\mu$m quantum cascade laser phase-locked to a state-of-the-art mid-infrared reference for precision molecular spectroscopy
• Selective Reflection Spectroscopy at the Interface between a Calcium Fluoride Window and Cs Vapour
• Casimir-Polder interaction of fullerene molecules with surfaces
• Testing the limits of the Maxwell distribution of velocities for atoms flying nearly parallel to the walls of a thin cell
• Spectroscopic Probe of the van der Waals Interaction between Polar Molecules and a Curved Surface

Cited by in corpus (2)

• Highly coherent phase-lock of an 8.1 $\mu$m quantum cascade laser to a turn-key mid-IR frequency comb
• Probing molecules in gas cells of subwavelength thickness with high frequency resolution