4Pi STED microscopy
Encyclopedia
The 4Pi-STED-microscope is the result of combining the two unrelated concepts of STED
- and 4Pi-microscopy
. Here, the fluorescent sample is placed in the common focus of two opposing lenses, but excitation and detection are performed through a single lens (4Pi mode A). The green excitation pulse is immediately followed by a red STED-pulse, which enters the focal region through both lenses inducing stimulated emission of the excited fluorescent molecules to the ground state. To permit fluorescence emission from the center but suppress it from neighbouring regions it is useful to phaseshift the STED beam to have a minimum at the center.
STED microscopy
Stimulated Emission Depletion microscopy, or STED microscopy, is a fluorescence microscopy technique that uses the non-linear de-excitation of fluorescent dyes to overcome the resolution limit imposed by diffraction with standard confocal laser scanning microscopes and conventional far-field...
- and 4Pi-microscopy
4Pi Microscope
A 4Pi Microscope is a laser scanning fluorescence microscope with an improved axial resolution. The typical value of 500-700 nm can be improved to 100-150 nm which corresponds to an almost spherical focal spot with 5-7 times less volume than that of standard confocal microscopy.-Working...
. Here, the fluorescent sample is placed in the common focus of two opposing lenses, but excitation and detection are performed through a single lens (4Pi mode A). The green excitation pulse is immediately followed by a red STED-pulse, which enters the focal region through both lenses inducing stimulated emission of the excited fluorescent molecules to the ground state. To permit fluorescence emission from the center but suppress it from neighbouring regions it is useful to phaseshift the STED beam to have a minimum at the center.