  Light-induced control of ions within small Coulomb crystals is investigated.
By intense intracavity optical standing wave fields, subwavelength localization
of individual ions is achieved for one-, two-, and three-dimensional crystals.
Based on these findings, we illustrate numerically how the application of such
optical potentials can be used to tailor the normal mode spectra and patterns
of multi-dimensional Coulomb crystals. The results represent, among others,
important steps towards controlling the crystalline structure of Coulomb
crystals, investigating heat transfer processes at the quantum limit and
quantum simulations of many-body systems.
