Evidence of superradiance in large PIC nanowires

Molecular J-aggregates are ideal for studying superradiance due to their tendency to align transition dipole moments in a "heads-to-tails" configuration. This alignment results in a narrow absorption band and increased radiative rates.¹ However, labeling J and H aggregates, which originates from Kasha's exciton theory², fails with large 2D structures due to their complex packing arrangements. This complexity gives rise to a third aggregate type, I-aggregates, which can show evidence of superradiance.³ We report new superradiant features in a recently identified nanowire I-aggregate formed with pseudocyanine iodide.⁴ These large I-aggregates exhibit different spectral characteristics compared to the well-characterized smaller J-aggregates. In addition to standard superradiant characteristics observed in molecular aggregates, we performed photon statistics studies that revealed bunching in second-order correlation measurements at room temperature. Notably, due to the fragile nature of these aggregates, such measurements have not yet been successfully performed in any molecular system with more than two emitters.⁵

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