Atomic selfordering in a ring cavity with counterpropagating pump

TL;DR

This paper demonstrates how a ring cavity with counterpropagating pumps can induce both self-ordering and CARL instabilities, enabling control over particle acceleration and trapping.

Contribution

It introduces a unified system that exhibits both self-ordering and CARL phenomena, with a phase diagram showing controllable transitions between these states.

Findings

System exhibits both self-ordering and CARL instabilities.

Phase diagram maps regions of different collective behaviors.

Control of cavity driving enables particle acceleration and trapping.

Abstract

The collective dynamics of mobile scatterers and light in optical resonators generates complex behaviour. For strong transverse illumination a phase transition from homogeneous to crystalline particle order appears. In contrast, a gas inside a single-side pumped ring cavity exhibits an instability towards bunching and collective acceleration called collective atomic recoil lasing (CARL). We demonstrate that by driving two orthogonally polarized counter propagating modes of a ring resonator one realises both cases within one system. The corresponding phase diagram depending on the two pump intensities exhibits regions in which either a generalized form of self-ordering towards a travelling density wave with constant centre of mass velocity or a CARL instability is formed. Controlling the cavity driving then allows to accelerate or slow down and trap a sufficiently dense beam of linearly polarizable particles.