Observation of energy oscillation between strongly-coupled counter-propagating ultra-high Q whispering gallery modes

Abstract

We report the first experimental observation of an energy oscillation between two coupled ultra-high Q whispering gallery modes in the time domain. Two counter-propagating whispering gallery modes in a silica toroid microcavity were employed for this purpose. The combination of a large coupling coefficient between the two modes and an ultra-high Q factor, which creates a large Γ value of > 10, results in a clear energy oscillation. Our measurement is based on a drop-port measurement technique, which enables us to observe the light energy in the two modes directly. The oscillation period measured in the time domain precisely matched that inferred from mode splitting in the frequency domain, and the measured results showed excellent agreement with results calculated with the developed numerical model.

Modulational instability and frequency combs in whispering-gallery-mode microresonators with backscattering

“…Also frequency comb generation at normal group velocity dispersion (GVD) was demonstrated in case of the coupling between different co-propagating spatial or polarizational mode families existing simultaneously in the microresonators [22][23][24]. Recently a number of results on the impact of the linear and nonlinear couplings between the counter-propagating waves has been reported [25,26] including generation of DKS [27][28][29]. However, the absence of the consistency and transparent justification of the applied models call for a revision of this problem in * noxobar@mail.ru the view of its persistent importance for practical applications.…”

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“…In this Section, we demonstrate that there are both slow and fast time scales inside the nonlinear terms in Eqs. (30), and that the latter can be eliminated resulting in a simpler and better balanced system of equations for the A ± µ amplitudes, see Eqs. (14), (39).…”

Strong Coupling in Microcavity Structures: Principle, Design, and Practical Application

“…theoretically investigated coupling interaction between molecule excitons and whispering gallery modes (WGMs), which approaches the limit of single exciton strong coupling in hyperbolic metamaterial cavity, composed of a dielectric core wrapped by several stacks of alternative layers of metal and dielectric. Yoshiki et al . studied cavity dynamics, in particular strong coupled system time response with ultrahigh‐quality factors.…”

“…theoretically investigated strong coupling effects between molecular excitons and WGMs. Yoshiki et al . first observed dynamic cavity strong coupling effects between time domain–based modes with ultrahigh‐quality factors.…”