Outshining molecular disorder with light.

When molecules interact strongly with light in an optical cavity (an arrangement of mirrors that confine light waves), molecular polaritons—part-photon, part–molecular entities—arise. These hybrid light-matter states can, in principle, carry energy through materials in a wavelike manner. This property has sparked considerable interest in the potential of polaritons to reshape energy transport in materials in ways that could not otherwise be achieved (1, 2). The challenge is that fluctuations in energy levels, ubiquitous in molecular systems, disrupt polariton coherence (long-range correlations of phase and amplitude of waves). This energetic disorder limits a polariton's ability to transport energy effectively. On page 845 of this issue, Yin et al. (3) report quantitative conditions under which polariton-mediated processes can be sustained against disorder. The finding offers a practical road map for harnessing strong light-matter interactions to achieve robust energy transport and enhanced functionality in molecular materials. [ABSTRACT FROM AUTHOR]