Small slot waveguide rings for on-chip quantum optical circuits

TL;DR

This paper investigates small slot waveguide rings for on-chip quantum optics, predicting high emitter-waveguide coupling efficiencies and emission enhancements, enabling advanced quantum circuits with controllable emitter interactions.

Contribution

It combines simulations and theory to show that tiny slot waveguide rings can achieve near-unity coupling and emission control, advancing integrated quantum photonics.

Findings

Near-unity emitter-waveguide coupling efficiencies (~1300 emission enhancement)

Strong and weak coupling regimes achievable in micron-sized rings

Directional emission coupling with high efficiency

Abstract

Nanophotonic interfaces between single emitters and light promise to enable new quantum optical technologies. Here, we use a combination of finite element simulations and analytic quantum theory to investigate the interaction of various quantum emitters with slot-waveguide rings. We predict that for rings with radii as small as 1.44 $\mu$m (Q = 27,900), near-unity emitter-waveguide coupling efficiencies and emission enhancements on the order of 1300 can be achieved. By tuning the ring geometry or introducing losses, we show that realistic emitter-ring systems can be made to be either weakly or strongly coupled, so that we can observe Rabi oscillations in the decay dynamics even for micron-sized rings. Moreover, we demonstrate that slot waveguide rings can be used to directionally couple emission, again with near-unity efficiency. Our results pave the way for integrated solid-state quantum circuits involving various emitters.