Controllable Fast and Slow Light in Photonic-Molecule Optomechanics with Phonon Pump.

Huajun Chen

doi:10.3390/mi12091074

Abstract

We theoretically investigate the optical output fields of a photonic-molecule optomechanical system in an optomechanically induced transparency (OMIT) regime, in which the optomechanical cavity is optically driven by a strong pump laser field and a weak probe laser field and the mechanical mode is driven by weak coherent phonon driving. The numerical simulations indicate that when the driven frequency of the phonon pump equals the frequency difference of the two laser fields, we show an enhancement OMIT where the probe transmission can exceed unity via controlling the driving amplitude and pump phase of the phonon driving. In addition, the phase dispersion of the transmitted probe field can be modified for different parametric regimes, which leads to a tunable delayed probe light transmission. We further study the group delay of the output probe field with numerical simulations, which can reach a tunable conversion from slow to fast light with the manipulation of the pump laser power, the ratio parameter of the two cavities, and the driving amplitude and phase of the weak phonon pump.

Highlights

IntroductionCavity optomechanics (COM) systems [1,2], researching the interaction of the photon modes and phonon modes, have obtained great progress in fundamental researches and pragmatic applications in the past few years, including the ground state cooling [3,4,5,6,7], precision measurements [8,9,10,11,12,13,14], and quantum information processing [15,16,17,18]
Induced by the phenomenon of optomechanically induced transparency (OMIT) was observed and the OMIT-induced slow light effect was investigated [33]. When another optical cavity was introduced to the optomechanical system to form a photonic molecule optomechanics [56], we demonstrated that the tunable OMIT could realize the conversion from slow to fast light by controlling the coupling strength of the two optical cavities J
The above phenomena can be explained as follows: When there is no phonon pump in the system, the radiation pressure force coming from the pump laser field on the WGM cavity c applies to the mechanical mode changing the mechanical displacement of the phonon mode, which alters the frequency ωc of the optomechanical cavity c; as a result, the mechanical mode resonates near its coherent oscillation frequency in the condition of ∆c = ωm

Summary

Introduction

Cavity optomechanics (COM) systems [1,2], researching the interaction of the photon modes and phonon modes, have obtained great progress in fundamental researches and pragmatic applications in the past few years, including the ground state cooling [3,4,5,6,7], precision measurements [8,9,10,11,12,13,14], and quantum information processing [15,16,17,18]. Micromachines 2021, 12, 1074 system is further driven by a weak coherent mechanical field (with the driving frequency ωq ), considering the coupling between the photon modes and phonon modes, another two different optical components in the output field will appear: the first one is induced by the pump and probe laser fields (with frequencies ω p ± nΩ) and the second one is induced by the optical pump and phonon pump fields (with frequencies ω p ± mωq ), where. The results show that the steerable conversion from the slow light to fast light effect can be reached by controlling several parameters

Model and Theory

Numerical Results and Discussion

Conclusions