Super-Resonant Intracavity Coherent Absorption

TL;DR

This paper introduces super-resonant coherent absorption in coupled optical cavities, enabling enhanced light-matter interaction beyond traditional resonator quality limits, with potential applications in spectroscopy and sensing.

Contribution

It demonstrates a novel super-resonant absorption mechanism combining resonant interaction and coherent perfect absorption in coupled cavities.

Findings

Enhanced effective interaction pathlength proportional to finesse ratios.

Split modes with high sensitivity to intracavity loss.

Circumvents limitations of ultrahigh-Q resonators.

Abstract

The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption. We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot-ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy and optical sensing schemes