Buffer gas cooling of a continuous CO molecular beam

Area of Science:

• Atomic and Molecular Physics
• Quantum Technologies
• Physical Chemistry

Background:

• Buffer-gas cooling is essential for preparing ultracold molecules.
• Direct laser cooling requires efficient pre-cooling stages.
• Carbon monoxide (CO) is a molecule of interest for quantum applications.

Purpose of the Study:

• To characterize a continuous buffer gas cooled source for CO molecules.
• To optimize source performance by varying parameters like gas flow rate, nozzle size, and cell volume.
• To investigate the population distribution in specific rotational states.

Main Methods:

• Experimental setup for continuous buffer gas cooling.
• Varying gas flow rate, nozzle size, and internal cell volume.
• Beam characterization including intensity and velocity measurements.
• Analysis of population distribution in rotational states.

Main Results:

• Achieved a beam intensity of 2.5 × 10¹⁴ molecules/(s sr).
• Measured a beam velocity of approximately 160 m/s.
• Observed an unexpected population distribution in two rotational states, possibly due to lower internal cell temperature.

Conclusions:

• The characterized buffer gas source demonstrates high performance for CO molecules.
• The results provide insights for optimizing buffer-gas cooling techniques.
• This work enhances a key cooling stage, facilitating the use of molecules in quantum technologies.