Posts Tagged ‘Scanning’

Holding tight on feathers – structural specializations and attachment properties of the avian ectoparasite Crataerina pallida (Diptera, Hippoboscidae) [RESEARCH ARTICLE]

Dennis S. Petersen, Nils Kreuter, Lars Heepe, Sebastian Büsse, Arndt H. J. Wellbrock, Klaudia Witte, and Stanislav N. GorbThe louse fly Crataerina pallida is an obligate blood-sucking ecto-parasite of the common swift Apus apus. Due to reducti…

Tracking the ultrafast motion of a single molecule by femtosecond orbital imaging

Watching a single molecule move on its intrinsic timescale has been one of the central goals of modern nanoscience, and calls for measurements that combine ultrafast temporal resolution with atomic spatial resolution. Steady-state experiments access the requisite spatial scales, as illustrated by direct imaging of individual molecular orbitals using scanning tunnelling microscopy or the acquisition of tip-enhanced Raman and luminescence spectra with sub-molecular resolution. But tracking the intrinsic dynamics of a single molecule directly in the time domain faces the challenge that interactions with the molecule must be confined to a femtosecond time window. For individual nanoparticles, such ultrafast temporal confinement has been demonstrated by combining scanning tunnelling microscopy with so-called lightwave electronics, which uses the oscillating carrier wave of tailored light pulses to directly manipulate electronic motion on timescales faster even than a single cycle of light. Here we build on ultrafast terahertz scanning tunnelling microscopy to access a state-selective tunnelling regime, where the peak of a terahertz electric-field waveform transiently opens an otherwise forbidden tunnelling channel through a single molecular state. It thereby removes a single electron from an individual pentacene molecule’s highest occupied molecular orbital within a time window shorter than one oscillation cycle of the terahertz wave. We exploit this effect to record approximately 100-femtosecond snapshot images of the orbital structure with sub-ångström spatial resolution, and to reveal, through pump/probe measurements, coherent molecular vibrations at terahertz frequencies directly in the time domain. We anticipate that the combination of lightwave electronics and the atomic resolution of our approach will open the door to visualizing ultrafast photochemistry and the operation of molecular electronics on the single-orbital scale.

Brilliant photos of little life-forms are taken with a laser-scanning microscope

A super-duper, confocal laser-scanning microscope lets us peer at the amazing details of nature.


The disclosed technology brings histopathology into the operating theatre, to enable real-time intra-operative digital pathology. The disclosed technology utilizes confocal imaging devices image, in the operating theatre, “optical slices” of fresh …

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