Rovibrational optical cooling of a molecular beam

Abstract

Cooling the rotation and the vibration of molecules by broadband light sources was possible for trapped molecular ions or ultracold molecules. Because of a low power spectral density, the cooling timescale has never fell below than a few milliseconds. Here we report on rotational and vibrational cooling of a supersonic beam of barium monofluoride molecules in less than 440 $\mu$s. Vibrational cooling was optimized by enhancing the spectral power density of a semiconductor light source at the underlying molecular transitions allowing us to transfer all the populations of $v^{\prime \prime }=1-3$ into the vibrational ground state ($v^{\prime \prime }=0$). Rotational cooling, that requires an efficient vibrational pumping, was then achieved. According to a Boltzmann fit, the rotation temperature was reduced by almost a factor of 10. In this fashion, the population of the lowest rotational levels increased by more than one order of magnitude.

References in corpus (7)

• Cold molecules: Progress in Quantum Engineering of Chemistry and Quantum Matter
• Optical pumping and vibrational cooling of molecules
• Controlling open quantum systems: Tools, achievements, and limitations
• Laser Cooling of Molecular Anions
• Rovibrational cooling of molecules by optical pumping
• Structures, Branching Ratios and Laser Cooling Scheme for 138BaF Molecule
• A supersonic beam of cold lithium hydride molecules

Cited by in corpus (10)

• Controlling the scattering length of ultracold dipolar molecules
• Buffer-gas cooling, high-resolution spectroscopy and optical cycling of barium monofluoride molecules
• Cooling of a Zero-Nuclear-Spin Molecular Ion to a Selected Rotational State
• Lifetime Measurements of the $A^2{\Pi }_{1/2}$ and $A^2{\Pi }_{3/2}$ States in BaF
• Saturated absorption spectroscopy of buffer-gas-cooled Barium monofluoride molecules
• Generation of rotational ground state HD${}^{+}$ ions in an ion trap using a resonance-enhanced threshold photoionization process
• Laser cooling of barium monofluoride molecules using synthesized optical spectra
• Isotopologue-selective laser cooling of molecules
• Determining a vibrational distribution with a broadband optical source
• Photon spin molasses for laser cooling molecular rotation