Strong coupling between photonic modes and molecular electronic excitations, creating hybrid light-matter states called polaritons, is an attractive avenue for controlling chemical reactions. Nevertheless, experimental demonstrations of polariton-modified chemical reactions remain sparse. Here, we demonstrate modified photoisomerization kinetics of merocyanine and diarylethene by coupling the reactant’s optical transition with photonic microcavity modes. We leverage broadband Fourier-plane optical microscopy to noninvasively and rapidly monitor photoisomerization within microcavities, enabling systematic investigation of chemical kinetics for different cavity-exciton detunings and photoexcitation conditions. We demonstrate three distinct effects of cavity coupling: first, a renormalization of the photonic density of states, akin to a Purcell effect, leads to enhanced absorption and isomerization rates at certain wavelengths, notably red-shifting the onset of photoisomerization. This effect is present under both strong and weak light-matter couplings. Second, kinetic competition between polariton localization into reactive molecular states and cavity losses leads to a suppression of the photoisomerization yield. Finally, our key result is that in reaction mixtures with multiple reactant isomers, exhibiting partially overlapping optical transitions and distinct isomerization pathways, the cavity resonance can be tuned to funnel photoexcitations into specific reactant isomers. Thus, upon decoherence, polaritons localize into a chosen isomer, selectively triggering the latter’s photoisomerization despite initially being delocalized across all isomers. This result suggests that careful tuning of the cavity resonance is a promising avenue to steer chemical reactions and enhance product selectivity in reaction mixtures.

中文翻译：

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通过极化子漏斗控制光子腔中的分子光异构化

光子模式和分子电子激发之间的强耦合，产生称为极化子的混合光物质态，是控制化学反应的一种有吸引力的途径。然而，极化激元改进的化学反应的实验演示仍然很少。在这里，我们通过将反应物的光学跃迁与光子微腔模式耦合来证明部花青和二芳基乙烯的改进的光异构化动力学。我们利用宽带傅立叶平面光学显微镜来非侵入性地快速监测微腔内的光异构化，从而能够系统地研究不同腔激子失谐和光激发条件的化学动力学。我们证明了腔耦合的三种不同效应：首先，光子态密度的重整化（类似于珀塞尔效应）导致某些波长下吸收和异构化速率的增强，特别是使光异构化的开始发生红移。这种效应在强光-物质耦合和弱光-物质耦合下都存在。其次，极化子定位到反应分子态和空腔损失之间的动力学竞争导致光异构化产率受到抑制。最后，我们的关键结果是，在具有多种反应物异构体的反应混合物中，表现出部分重叠的光学跃迁和不同的异构化途径，可以调节空腔共振以将光激发集中到特定的反应物异构体中。因此，在退相干时，极化子定位到选定的异构体中，选择性地触发后者的光致异构化，尽管最初在所有异构体中都离域。这一结果表明，仔细调整空腔共振是引导化学反应和提高反应混合物中产物选择性的有前途的途径。