Spatial coherence and stability in a disordered organic polariton condensate

TL;DR

This study investigates spatial coherence in a disordered organic polariton condensate, revealing long-range correlations, phase fluctuations, vortex formation, and the influence of disorder on coherence properties.

Contribution

It demonstrates the emergence of spatial coherence and phase dynamics in organic microcavities, highlighting effects of disorder and modulation instabilities in such systems.

Findings

Correlations extend over entire spot size.

g^{(1)}(r,r') nearly unity at short distances.

Vortex formation and phase fluctuations observed.

Abstract

Although only a handful of organic materials have shown polariton condensation, their study is rapidly becoming more accessible. The spontaneous appearance of long-range spatial coherence is often recognized as a defining feature of such condensates. In this work, we study the emergence of spatial coherence in an organic microcavity and demonstrate a number of unique features stemming from the peculiarities of this material set. Despite its disordered nature, we find that correlations extend over the entire spot size and we measure $g^{(1)}(r,r')$ values of nearly unity at short distances and of 50% for points separated by nearly 10 $\mu$m. We show that for large spots, strong shot to shot fluctuations emerge as varying phase gradients and defects, including the spontaneous formation of vortices. These are consistent with the presence of modulation instabilities. Furthermore, we find that measurements with flat-top spots are significantly influenced by disorder and can, in some cases, lead to the formation of mutually incoherent localized condensates.