Abstract: Provided herein is an apparatus, including an excitation arm including excitation optics; a collection arm including collection optics, wherein the excitation arm and the collection arm are geometrically off-axis from one another for independent control of the excitation optics or the collection optics; and a full-surface spectroscopic analyzer to analyze a thin-film over an article from Raman-scattered light collected by the collection optics.

Abstract: Certain nanocrystals possess exceptional optical properties that may make them valuable probes for biological imaging, but rendering these nanoparticles biocompatible requires that they be small enough not to perturb cellular systems. This invention describes a phosphorescent upconverting sub-10 nm nanoparticle comprising a lanthanide-doped hexagonal ?-phase NaYF4 nanocrystal and methods for making the same.

Abstract: Certain nanocrystals possess exceptional optical properties that may make them valuable probes for biological imaging, but rendering these nanoparticles biocompatible requires that they be small enough not to perturb cellular systems. This invention describes a phosphorescent upconverting sub-10 nm nanoparticle comprising a lanthanide-doped hexagonal ?-phase NaYF4 nanocrystal and methods for making the same.

Abstract: Provided herein is an apparatus, including an excitation arm including excitation optics; a collection arm including collection optics, wherein the excitation arm and the collection arm are geometrically off-axis from one another for independent control of the excitation optics or the collection optics; and a full-surface spectroscopic analyzer to analyze a thin-film over an article from Raman-scattered light collected by the collection optics.

Abstract: Various embodiments of the invention describe the synthesis of upconverting nanoparticles (UCNPs), lanthanide-doped hexagonal ?-phase sodium yttrium fluoride NaYF4:Er3+/Yb3 nanocrystals, less than 10 nanometers in diameter that are over an order of magnitude brighter under single-particle imaging conditions than existing compositions, allowing visualization of single UCNPs as small (d=4.8 nm) as fluorescent proteins. We use Advanced single-particle characterization and theoretical modeling is demonstrated to find that surface effects become critical at diameters under 20 nm, and that the fluences used in single-molecule imaging change the dominant determinants of nanocrystal brightness. These results demonstrate that factors known to increase brightness in bulk experiments lose importance at higher excitation powers, and that, paradoxically, the brightest probes under single-molecule excitation are barely luminescent at the ensemble level.