Dynamics of a buffer-gas-loaded, deep optical trap for molecules

TL;DR

This paper proposes a method for trapping small, stable molecules at cryogenic temperatures using a buffer-gas loaded deep optical trap, enabling new research avenues in molecular physics.

Contribution

It introduces a novel approach combining buffer-gas loading with a high-intensity optical trap for molecules, with theoretical analysis of dynamics and loss mechanisms.

Findings

Potential to trap 10^4 to 10^6 molecules

Trap depth of approximately 10 K achievable

Insensitive to molecular internal states

Abstract

We describe an approach to optically trapping small, chemically stable molecules at cryogenic temperatures by buffer-gas loading a deep optical dipole trap. The ~10 K trap depth will be produced by a tightly-focused, 1064-nm cavity capable of reaching intensities of hundreds of GW/cm$^2$. Molecules will be directly buffer-gas loaded into the trap using a helium buffer gas at 1.5 K. The very far-off-resonant, quasielectrostatic trapping mechanism is insensitive to a molecule's internal state, energy level structure, and its electric and magnetic dipole moment. Here, we theoretically investigate the trapping and loading dynamics, as well as the heating and loss rates, and conclude that $10^4$-$10^6$ molecules are likely to be trapped. Our trap would open new possibilities in molecular spectroscopy, studies of cold chemical reactions, and precision measurement, amongst other fields of physics.