A cryofuge for cold-collision experiments with slow polar molecules

TL;DR

This paper introduces the cryofuge, a novel method that uses centrifugal force to produce dense, slow, ultracold molecular samples suitable for collision studies, advancing research in ultracold chemistry and physics.

Contribution

The cryofuge technique uniquely combines cryogenic cooling with centrifugal acceleration to achieve ultracold, dense molecular samples with high flux and long interaction times.

Findings

Achieved molecular velocities below 20 m/s

Produced densities exceeding 10^9/cm^3

Observed and characterized cold dipolar collisions

Abstract

Ultracold molecules represent a fascinating research frontier in physics and chemistry, but it has proven challenging to prepare dense samples at low velocities. Here we present a solution to this goal by a non-conventional approach dubbed cryofuge. It employs centrifugal force to bring cryogenically cooled molecules to kinetic energies below $1\,$K$\times k_B$ in the laboratory frame, with corresponding fluxes exceeding $10^{10}$/s at velocities below $20\,$m/s. By attaining densities higher than $10^9$/cm$^3$ and interaction times longer than $25\,$ms in samples of fluoromethane as well as deuterated ammonia, we observe cold dipolar collisions between molecules and determine their collision cross sections.