1 research outputs found
Toward Label-Free Super-Resolution Microscopy
We
propose and implement a far-field spectroscopic system for imaging
below the diffraction limit without the need for fluorescence labeling.
Our technique combines concepts from Stimulated Emission Depletion
(STED) microscopy and Femtosecond Stimulated Raman Spectroscopy (FSRS).
The FSRS process generates signal through the creation of vibrational
coherences, and here we use a toroidal-shaped decoherence pulse to
eliminate vibrational signal from the edges of the focal spot. The
nonlinear dependence on decoherence pulse power enables subdiffraction
imaging. As in STED, the resolution is in theory infinitely small
given infinite decoherence pulse power. Here, we first experimentally
demonstrate that the photophysical principles behind our super-resolution
Raman imaging method are sound. We then prove that addition of the
decoherence pulse significantly improves the spatial resolution of
our microscope, achieving values beyond the diffraction limit. We
discuss future directions for this technique, including methods to
reach resolution on the order of ten nanometers