On-chip interference of scattering from two individual molecules in plastic

TL;DR

This paper demonstrates the coherent interference of two organic molecules coupled to a microresonator on a chip, showing potential for polymer-based quantum photonic circuits despite material challenges.

Contribution

It introduces a method to couple and tune two molecules in a plastic film to a microresonator, enabling controlled interference effects on a chip.

Findings

Large collective extinction observed in forward direction

Destructive interference of scattering in backward direction

Tuning of molecular resonance frequencies achieved

Abstract

Integrated photonic circuits offer a promising route for studying coherent cooperative effects of a controlled collection of quantum emitters. However, spectral inhomogeneities, decoherence and material incompatibilities in the solid state make this a nontrivial task. Here, we demonstrate efficient coupling of a pair of organic molecules embedded in a plastic film to a TiO$_2$ microdisc resonator on a glass chip. Moreover, we tune the resonance frequencies of the molecules with respect to that of the microresonator by employing nanofabricated electrodes. For two molecules separated by a distance of about 8$\,\mu$m and an optical phase difference of about $\pi/2$, we report on a large collective extinction of the incident light in the forward direction and the destructive interference of its scattering in the backward direction. Our work sets the ground for the coherent coupling of several molecules via a common mode and the realization of polymer-based hybrid quantum photonic circuits.