Accuracy of superlocalization imaging using Gaussian and dipole emission point-spread functions for modeling gold...

We present a study comparing the accuracy of superlocalization imaging of plasmon-mediated emission from gold nanorods (AuNRs) using both Gaussian and dipole emission point-spread function (PSF) models. By fitting the emission PSF of single AuNR luminescence, we have shown that a 3-axis dipole PSF gives improved localization accuracy over the Gaussian PSF, especially for nonplanar AuNRs, while also allowing the AuNR three-dimensional orientation and emission wavelength to be determined. On the other hand, when a single-axis dipole PSF model is applied to the AuNR emission, the fit estimates converge to values that are inconsistent with their experimentally measured values, affecting both the localization accuracy and precision of the fitted centroid position. These results indicate that when applying superlocalization techniques to plasmonic nanostructures, care must be taken to understand the nature of the emission before a correct dipole PSF can be applied.