Theory of enhanced dynamical photo-thermal bi-stability effects in cuprous oxide/organic hybrid heterostructure

TL;DR

This paper theoretically explores multiple bi-stability regions in a cuprous oxide/organic hybrid heterostructure, revealing significantly larger effects than in bulk cuprous oxide, with potential implications for nonlinear optical applications.

Contribution

It introduces a theoretical model demonstrating large-scale bi-stability effects in a hybrid heterostructure due to exciton resonance and thermal effects, surpassing previous experimental observations.

Findings

Multiple bi-stability regions are identified, exceeding bulk effects by three orders of magnitude.

Hysteresis-like temperature distribution is observed in numerical simulations.

Asymmetrical absorption behavior is found for different hybrid exciton branches.

Abstract

We theoretically demonstrate the formation of multiple bi-stability regions in the temperature pattern on the interface between a cuprous oxide quantum well and DCM2:CA:PS organic compound. The Frenkel molecular exciton of the DCM2 is brought into resonance with the $1S$ quadrupole Wannier-Mott exciton in the cuprous oxide by "solvatochromism" with CA. The resulting hybrid is thermalized with surrounding helium bath. This leads to strongly non-linear temperature dependence of the laser field detuning from the quadrupole exciton energy band which is associated with the temperature induced red shift of the Wannier exciton energy. Numerical up and down-scan for the detuning reveals hysteresis-like temperature distribution. The obtained \emph{multiple} bi-stability regions are at least three orders of magnitude bigger ($meV$) than the experimentally observed bi-stability in bulk cuprous oxide ($\mu eV$). The effective absorption curve exhibits highly asymmetrical behavior for the Frenkel-like (above the $1S$ energy) and Wannier-like (below the $1S$ energy) branches of the hybrid.