Super-resolution Imaging of Plasmonic Near-Fields: Overcoming Emitter Mislocalizations.

Plasmonic nano-objects have shown great potential in enhancing applications like biological/chemical sensing, light harvesting and energy transfer, and optical/quantum computing. Therefore, an extensive effort has been vested in optimizing plasmonic systems and exploiting their field enhancement properties. Super-resolution imaging with quantum dots (QDs) is a promising method to probe plasmonic near-fields but is hindered by the distortion of the QD radiation pattern.

Far-Field Super-resolution Detection of Plasmonic Near-Fields.

We demonstrate a far-field single molecule super-resolution method that maps plasmonic near-fields. The method is largely invariant to fluorescence quenching (arising from probe proximity to a metal), has reduced point-spread-function distortion compared to fluorescent dyes (arising from strong coupling to nanoscopic metallic features), and has a large dynamic range (of 2 orders of magnitude) allowing mapping of plasmonic field-enhancements regions. The method takes advantage of the sensitivity of quantum dot (QD) stochastic blinking to plasmonic near-fields.

Photon-HDF5: Open Data Format and Computational Tools for Timestamp-based Single-Molecule Experiments.

Archival of experimental data in public databases has increasingly become a requirement for most funding agencies and journals. These data-sharing policies have the potential to maximize data reuse, and to enable confirmatory as well as novel studies. However, the lack of standard data formats can severely hinder data reuse.

Photon-HDF5: An Open File Format for Timestamp-Based Single-Molecule Fluorescence Experiments.

We introduce Photon-HDF5, an open and efficient file format to simplify exchange and long-term accessibility of data from single-molecule fluorescence experiments based on photon-counting detectors such as single-photon avalanche diode, photomultiplier tube, or arrays of such detectors. The format is based on HDF5, a widely used platform- and language-independent hierarchical file format for which user-friendly viewers are available. Photon-HDF5 can store raw photon data (timestamp, channel number, etc.

Substituent effects on the reversibility of furan-maleimide cycloadditions.

The effects of furan and maleimide substitution on the dynamic reversibility of their Diels-Alder reactivity have been investigated computationally and by (1)H NMR spectroscopy. Furan and furan derivatives bearing methoxy, methyl, or formyl groups at their 2- or 3-positions were investigated with maleimide and maleimide derivatives bearing N-methyl, N-allyl, and N-phenyl substituents. Computational predictions indicate that electronic and regiochemical effects of furan substitution significantly influence their Diels-Alder reactivity with maleimide, with reaction free energies of exo adduct formation ranging from ΔG = -9.