Photonic Nanojet Enhanced Photoluminescence

This study proposes a novel technique for enhancing photoluminescence (PL) signal using a combination of a single dielectric microsphere attached to a stem and confocal micro-PL spectroscopy. The technique involves directing a laser through the glass microsphere to generate a photonic nanojet (PNJ), a narrow-focused, non-evanescent, and highly intense electromagnetic beam with subwavelength lateral sizes, and obtaining PL spectra. The PNJ enhanced PL method was tested on NBP glass doped with CdZnSeS quantum dot (QD), 0.1 wt% of Praseodymium ion ($\mathrm{Pr}^{3+}$) ions, and 5 times enhancement was observed for the PL signal from $\mathrm{Pr}^{3+}$ ion.