2024
, Q1
Article
Uncovering new ways for light localization at the micro- and nanoscale is essential for the development of state-of-the-art photonic devices. Nowadays the most advances in this area are achieved using near-field resonators, providing extreme light confinement in nanoscale volume. However, the boosting of device performance in some practical applications, for example, luminescent sensing, optical tweezing, and super-resolution optical microscopy require light localization at distances beyond near-field range. This issue can be addressed by employing dielectric microstructures that produce photonic nanojets (PNJs), representing an intermediate state between near-field localization and geometric optics. Despite the promising benefits of PNJ implementation in various optical applications, their practical studies are scarce and mostly limited to numerical simulations. Here, a new type of PNJ is introduced and studied both numerically and experimentally. Contrary to the conventional case, wherein PNJ is generated by a single microstructure, the reported PNJ is produced through collective effects in a densely packed array of dielectric microstructures. The studies reveal that these collective PNJs can reach an unprecedented length of >60 λ, while maintaining a high localization intensity. Under certain configurations of the array, collective PNJ can enhance the electromagnetic field by up to sevenfold, being a versatile tool for various photonic applications.
https://doi.org/10.1002/adom.202401259