Casimir Light in Dispersive Nanophotonics

Time-varying optical media, whose dielectric properties are actively modulated in time, introduce a host of novel effects in the classical propagation of light, and are of intense current interest. In the quantum domain, time-dependent media can be used to convert vacuum fluctuations (virtual photons) into pairs of real photons. We refer to these processes broadly as dynamical vacuum effects (DVEs). Despite interest for their potential applications as sources of quantum light, DVEs are generally very weak, presenting many opportunities for enhancement through modern techniques in nanophotonics, such as using media which support excitations such as plasmon and phonon polaritons. Here, we present a theory of weakly modulated DVEs in arbitrary nanostructured, dispersive, and dissipative systems. A key element of our framework is the simultaneous incorporation of time-modulation and dispersion through time-translation-breaking linear response theory. As an example, we use our approach to propose a highly efficient scheme for generating entangled surface polaritons based on time-modulation of the optical phonon frequency of a polar insulator.

Automated summary

Time-varying optical media with actively modulated dielectric properties introduce novel effects in light propagation and are of current interest. In the quantum domain, time-dependent media can convert vacuum fluctuations into real photons. Despite being weak, these dynamical vacuum effects (DVEs) can be enhanced through nanophotonics techniques. This study presents a theory of weakly modulated DVEs in arbitrary nanostructured systems, incorporating time-modulation and dispersion through time-translation-breaking linear response theory. An efficient scheme for generating entangled surface polaritons is proposed based on time-modulation of the optical phonon frequency of a polar insulator.