Pathway interference in a loop array of three coupled microresonators

Abstract

A system of three coupled toroidal microresonators arranged in a loop configuration is studied. This setup allows light entering the resonator setup from a tapered fiber to evolve along a variety of different pathways before leaving again through the fiber. In particular, the loop configuration of the resonators allows for an evolution which we term roundtrip process, in which the light evolves from one resonator sequentially through all others back to the initial one. This process renders the optical properties of the system sensitive to the phases of all coupling and scattering constants in the system. We analyze the transmission and reflection spectra, and interpret them in terms of interference between the various possible evolution pathways through the resonator system. In particular, we focus on the phase dependence of the optical properties. Finally, we discuss possible applications for this phase sensitivity induced by the roundtrip process, such as the measurement of the position of a nanoparticle close to one of the resonators, and the measurement of changes in the refractive index between two resonators. Our analytical results for the applications are supported by proof-of-principle calculations based on finite-difference-time-domain solution of Maxwell's equations in two dimensions on a grid.

Interaction of whispering gallery modes in integrated optical microring or microdisk circuits: hybrid coupled mode theory model

“…[43]. Further recent studies include the ab-initio HCMT model [4], based on the bend mode viewpoint, a parametric pathway analysis for purposes of application as a sensor [44], and an approximate analytical WGM-based description [45] that led to experimental observations [46]. Results of the present WGM-HCMT model are summarized in Figure 9.…”

Directional emission of dielectric disks with a finite scatterer in the THz regime

“…The light propagation is thus simulated by the Finite-Difference Time-Domain (FDTD) Method [3,13,17]. The geometry of waveguide and resonator as well as the material properties are chosen as in the experiment, without fine-tuning of any of the parameters.…”

“…But while the detector exclusively monitors the far field radiation component of the emission, the vicinity of the resonator is strongly influenced by near field contributions. Thus, a transformation of the FDTD results into the far field is required [3,13,17]. To this end, we calculate the amplitude and the phase of the electric and magnetic fields on a circle around the resonator center, with radius larger than the resonator radius by a variable offset ρ.…”

Tunable slowing, storing, and releasing of a weak microwave field

“…The light trapped in coupled resonators display the pathway interference [5][6][7][8][9] similar to the quantum interference in atoms [2]. This path interference induces the optical analog of EIT in coupled optical resonators [5][6][7] and optomechanics [10,11] has been demonstrated for slow light.…”