Optomechanics with molecules in a strongly pumped ring cavity

TL;DR

This paper proposes a novel cavity optomechanical cooling scheme for molecules using a strongly driven ring cavity in the sideband regime, enabling fast and potentially ground-state cooling despite weak single-molecule coupling.

Contribution

It introduces a method to achieve efficient molecular cooling by leveraging collective enhancement in a strongly pumped ring cavity, overcoming challenges of weak coupling and lack of closed transitions.

Findings

Predicted fast cooling of molecules in a ring cavity setup.

Showed ground state cooling is possible near the Anti-stokes sideband.

Demonstrated continuous monitoring of molecular quantum jumps.

Abstract

Cavity cooling of an atom works best on a cyclic optical transition in the strong coupling regime near resonance, where small cavity photon numbers suffice for trapping and cooling. Due to the absence of closed transitions a straightforward application to molecules fails: optical pumping can lead the particle into uncoupled states. An alternative operation in the far off-resonant regime generates only very slow cooling due to the reduced field-molecule coupling. We predict to overcome this by using a strongly driven ring-cavity operated in the sideband cooling regime. As in the optomechanical setups one takes advantage of a collectively enhanced field-molecule coupling strength using a large photon number. A linearized analytical treatment confirmed by full numerical quantum simulations predicts fast cooling despite the off-resonant small single molecule - single photon coupling. Even ground state cooling can be obtained by tuning the cavity field close to the Anti-stokes sideband for sufficiently high trapping frequency. Numerical simulations show quantum jumps of the molecules between the lowest two trapping levels, which can be be directly and continuously monitored via scattered light intensity detection.