# Tunable strong coupling of two adjacent optical \lambda/2 Fabry-P\'erot microresonators

## TL;DR

This paper demonstrates tunable strong coupling between two adjacent optical microresonators, showing anticrossing behavior and controllable coupling rates, advancing understanding of hybrid mode formation in microresonator systems.

## Contribution

It introduces a method to actively tune the resonance of one microresonator across another, enabling controlled strong coupling and providing a model system for studying coupled cavity modes.

## Key findings

- Clear anticrossing in transmission spectra confirms strong coupling.
- Coupling rate can be tuned by changing resonator geometry.
- Coupled system modeled by coupled damped harmonic oscillators.

## Abstract

Optical half-wave microresonators enable to control the optical mode density around a quantum system and thus to modify the temporal emission properties. If the coupling rate exceeds the damping rate, strong coupling between a microresonator and a quantum system can be achieved, leading to a coherent energy exchange and the creation of new hybrid modes. Here, we investigate strong coupling between two adjacent lambda/2 Fabry-P\'erot microresonators, where the resonance of one microresonator can be actively tuned across the resonance of the other microresonator. The transmission spectra of the coupled microresonators show a clear anticrossing behavior, which proves that the two cavity modes are strongly coupled. Additionally, we can vary the coupling rate by changing the resonator geometry and thereby investigate the basic principles of strong coupling with a well-defined model system. Finally, we will show that such a coupled system can theoretically be modelled by coupled damped harmonic oscillators.

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Source: https://tomesphere.com/paper/1908.01566