J-aggregates’ quantum properties uniquely shield light signals from fragmentation

Maxim Sukharev of Arizona State University has demonstrated a way to shield light signals from degradation within molecular ensembles. The work reveals that a phenomenon called spectral starvation diminishes optical signals, and is countered by the revival of polaritonic double-quantum coherences. This revival is governed by a relationship linking molecular properties to macroscopic effects, establishing a pathway to engineer optical nonlinearities. For J-aggregates, where excitonic coupling is less than zero, this resonance uniquely protects coherence from spatial fragmentation by isolating a resonant state. Molecular ensembles experiencing strong light-matter coupling can revive genuine polaritonic double-quantum coherences (DQCs), countering a phenomenon that diminishes optical signals. This reversal occurs despite collective cavity delocalization driving the macroscopic nonlinear…