Diffusion, thermalization and optical pumping of YbF molecules in a cold buffer gas cell

Abstract

We produce YbF molecules with a density of 10^18 m^-3 using laser ablation inside a cryogenically-cooled cell filled with a helium buffer gas. Using absorption imaging and absorption spectroscopy we study the formation, diffusion, thermalization and optical pumping of the molecules. The absorption images show an initial rapid expansion of molecules away from the ablation target followed by a much slower diffusion to the cell walls. We study how the time constant for diffusion depends on the helium density and temperature, and obtain values for the YbF-He diffusion cross-section at two different temperatures. We measure the translational and rotational temperatures of the molecules as a function of time since formation, obtain the characteristic time constant for the molecules to thermalize with the cell walls, and elucidate the process responsible for limiting this thermalization rate. Finally, we make a detailed study of how the absorption of the probe laser saturates as its intensity increases, showing that the saturation intensity is proportional to the helium density. We use this to estimate collision rates and the density of molecules in the cell.

20 pages, 11 figures, minor revisions following referee suggestions

References in corpus (8)

• Cold and Ultracold Molecules: Science, Technology, and Applications
• Using Molecules to Measure Nuclear Spin-Dependent Parity Violation
• Search for the electric dipole moment of the electron with thorium monoxide
• Electrostatic extraction of cold molecules from a cryogenic reservoir
• Lifetime of the A(v'=0) state and Franck-Condon factor of the A-X(0-0) transition of CaF measured by the saturation of laser-induced fluorescence
• Production of long-lived atomic vapor inside high-density buffer gas
• Doppler-free laser spectroscopy of buffer gas cooled molecular radicals
• Transport of polar molecules by an alternating gradient guide

Cited by in corpus (30)

• The Buffer Gas Beam: An Intense, Cold, and Slow Source for Atoms and Molecules
• Optical diagnostics of laser-produced plasmas
• Measuring the electric dipole moment of the electron in BaF
• Measurement of the electron's electric dipole moment using YbF molecules: methods and data analysis
• Design for a fountain of YbF molecules to measure the electron's electric dipole moment
• Methods, Analysis, and the Treatment of Systematic Errors for the Electron Electric Dipole Moment Search in Thorium Monoxide
• A buffer gas beam source for short, intense and slow molecular pulses
• Buffer-gas cooling, high-resolution spectroscopy and optical cycling of barium monofluoride molecules
• Enhanced Yield from a Cryogenic Buffer Gas Beam Source via Excited State Chemistry
• BaH molecular spectroscopy with relevance to laser cooling
• Cold collision and high-resolution spectroscopy of buffer gas cooled BaF Molecule
• Franck-Condon Factors and Radiative Lifetime of the A^{2}Π_{1/2} - X^{2}Σ^{+} Transition of Ytterbium Monoflouride, YbF
• Characterization of a cryogenic beam source for atoms and molecules
• Cryogenic Buffer Gas beams of AlF, CaF, MgF, YbF, Al, Ca, Yb and NO -- a comparison
• Cold, anisotropically-interacting van der Waals molecule: TiHe
• Searching for New Physics Through AMO Precision Measurements
• Method for traveling-wave deceleration of buffer-gas beams of CH
• Simulation of Cryogenic Buffer Gas Beams
• Low-temperature spectroscopy of the ${}^{12}$C${}_2$H${}_2$ (${\upsilon }_1+{\upsilon }_3$) band in a helium buffer gas
• Influence of source parameters on the longitudinal phase-space distribution of a pulsed cryogenic beam of barium fluoride molecules
• Production of carbon clusters ${\text{C}}_3$ to ${\text{C}}_{12}$ with a cryogenic buffer-gas beam source
• Fast and High-Yield Loading of a D${}_2$ MOT of Potassium from a Cryogenic Buffer Gas Beam
• Fine Structure of Open Shell Diatomic Molecules in Combined Electric and Magnetic Fields
• Slow molecular beams from a cryogenic buffer gas source
• Measurement of Doppler effects in cryogenic buffer-gas cell
• Dynamics of translational and rotational thermalization of AlF molecules via collisions with cryogenic helium
• Photon spin molasses for laser cooling molecular rotation
• Production and spectroscopy of cold radioactive molecules
• Chemistry in a Cryogenic Buffer Gas Cell
• Prospects for the measurement of the electron electric dipole moment using YbF