Theory of resonant radiation force exerted on nanostructures by optical excitation of their quantum states: From microscopic to macroscopic descriptions

We establish a theoretical framework that provides a bridge between the microscopic to macroscopic descriptions of the radiation force (RF) under a quantum resonance condition. By using this framework, we derive an explicit analytical expression to clearly demonstrate the properties of the resonant RF on nanostructures and related novel phenomena. (i) For a single nano-object the RF drastically changes with the size, shape, and quality of a nano-object due to the spatial correlations of the internal radiation field and the matter-excited states. This property is highly advantageous in the selective manipulation of quantum properties of nano-objects. (ii) For multiple nano-objects an attractive (repulsive) interobject radiation force (IRF) arises between nano-objects under the optical excitation of a particular coupled state of their spatially separated polaritons, and we term this state as “polaritonic molecule.” This IRF can be enhanced even between the nano-objects that have a large spatial separation if there exist intermediate nano-objects even with very weak induced polarizations, and this effect is termed as “superinterobject radiation force.” In addition, we clarify that a “negative dissipative force” arises when the electronic polarization in a particular nano-object is inverted by a photomediated interaction. Since the resonant RF and IRF depend on many degrees of freedom of both nanostructures and light, they will provide a great variety of optical control methods for the collective dynamics of nanocomposite materials.