Mirror-mediated cooling: a paradigm for particle cooling via the retarded dipole force

The dipole force, which is generally conservative and thus unable to cool or heat a particle’s motion, acquires a dissipative nature when invested with some form of memory. We consider here the use of a single mirror, placed at a suitable distance from the particle, as the delay element or memory. This geometry, which may be considered as the prototype for cavity-mediated cooling, itself offers a realistic cooling mechanism, and for a one-dimensional example we find cooling times of milliseconds and limiting temperatures in the milllikelvin range. The cooling force is in principle applicable to atoms, molecules, particles and nanostructures, and can be enhanced through the use of optical resonances, perhaps plasmonic or geometric in origin, in the mirror, and by the inclusion of gain within the optical feedback path.