Quantifying the local density of optical states of nanorods by fluorescence lifetime imaging

In this paper, we demonstrate a facile far-field approach to quantify the near-field local density of optical states (LDOS) of a nanorod using CdTe quantum dot (QD) emitters tethered to the surface of the nanorods as beacons for optical read-outs. The radiative decay rate was extracted to quantify the LDOS; our analysis indicates that the LDOS of the nanorod enhances both the radiative and nonradiative decay of QDs, particularly the radiative decay of QDs at the end of a nanorod is enhanced by 1.17 times greater than that at the waist, while the nonradiative decay was enhanced uniformly over the nanorod. To the best of our knowledge, our effort constitutes the first to map the LDOS of a nanostructure via the far-field method, to provide clarity on the interaction mechanism between emitters and the nanostructure, and to be potentially employed in the LDOS mapping of high-throughput nanostructures.