Analytical Model and Solution Illustrating Classical Optical Contribution to Giant Spectral Splitting in Strongly-Coupled Micro/nanocavity-atom System

Jian Zeng,Zhi-Yuan Li

doi:10.3389/fphy.2022.734841

Abstract

Many experimental observations have shown remarkably large or even giant spectral splitting in strongly-coupled micro/nanocavity-atom systems. Popularly, such a spectral splitting has been attributed to the Rabi splitting, a pure quantum mechanical effect. However, there are disputes regarding whether the spectral splitting caused by multiple emitters, such as excitons in J-aggregate of molecules, is a pure quantum effect or also contributed by classical optical effect. In this work, we address this difficult problem by building a model physical system of a practical Fabry-Perot high-Q optical microcavity involving Lorentz-dispersion atoms. Very interestingly, by performing evaluation and estimate upon several strongly-coupled cavity-atom systems, we have found that the classical optical splitting and quantum Rabi splitting can be in the same order of magnitude. Our studies clearly indicate that the phenomenon of “giant Rabi splitting” that has been extensively observed in many experiments can also be caused by classic optical effects in addition to quantum mechanical effect. In some cases, the contribution by classic optical effects may be comparable to or even exceeding the contribution from quantum effects. We expect that this work can constructing the true and complete physics picture underlying strong light-matter interaction in a micro/nanocavity system.

Highlights

Strong coupling of quantum emitter with cavity is important for a wide range of application and studies, such as quantum cryptography [17], quantum information processing [25], nano-optical circuits [29], single-photon switch [31], and single-atom laser [19]
Many previous experimental works reported that a suitable adjustment of resonant micro/nanocavity parameters can improve the quantum interacting effect to obtain a “giant Rabi splitting”, which is reflected from practical experimental observation of giant spectral splitting
We find that the classic dispersion effect of cavity medium can induce a tunable spectral splitting whose magnitude can be large

Summary

INTRODUCTION

Strong coupling of quantum emitter with cavity is important for a wide range of application and studies, such as quantum cryptography [17], quantum information processing [25], nano-optical circuits [29], single-photon switch [31], and single-atom laser [19]. [37], where quantum versus optical interaction contribution to giant spectral splitting in a strongly coupled nanogap plasmon–molecules system was discussed in details This theoretical work has modeled surface plasmon resonances and molecules as two kinds of Lorentzian oscillators in mutual strong optical interaction. The transmission spectrum of an incident light as probe signal can be analyzed and it will deflect the spectral response of this microcavity-atoms coupled system, from which the influence of the classical optical interaction upon the atomic spectrum can be revealed and the underlying physical mechanism can be clarified This system can well model and describe a practical cavity-molecule strong interaction. In this paper we have used this method to calculate the transmission spectrum when the cavity medium is a dispersion medium with Lorentz lineshape, and found that the spectrum is split purely attributed to the classic optical interaction rather than quantum mechanical interaction. We only discuss the first resonance peak here, but other high-order resonance peaks of the microcavity obey the same rule

RESULTS

CONCLUSION

DATA AVAILABILITY STATEMENT