History
In 1971, Christoph Cremer and Thomas Cremer proposed the creation of a perfect hologram, i.e. one that carries the whole field information of the emission of a point source in all directions, a so-called hologram.
The first description of a practicable system of 4Pi microscopy, i.e. the setup with two opposing, interfering lenses, was invented by Stefan Hell in 1991. He could demonstrate it experimentally also in 1994.
In the following years the number of applications for this microscope have grown. Parallel excitation and detection with 64 spots in the sample simultaneously combined with the improved spatial resolution resulted in the successful recording of the dynamics of mitochondria in yeast cells with a 4Pi microscope in 2002.
A commercial version was launched by microscope manufacturer Leica Microsystems in 2004.
Up to now, the best quality in a 4Pi microscope was reached in conjunction with the STED principle. Using a 4Pi microscope with appropriate excitation and de-excitation beams it was possible to create a uniformly 50 nm sized spot which corresponds to a decreased focal volume compared to confocal microscopy by a factor of 150–200.
Read more about this topic: 4Pi Microscope
Famous quotes containing the word history:
“The foregoing generations beheld God and nature face to face; we, through their eyes. Why should not we also enjoy an original relation to the universe? Why should not we have a poetry and philosophy of insight and not of tradition, and a religion by revelation to us, and not the history of theirs?”
—Ralph Waldo Emerson (1803–1882)
“There is a constant in the average American imagination and taste, for which the past must be preserved and celebrated in full-scale authentic copy; a philosophy of immortality as duplication. It dominates the relation with the self, with the past, not infrequently with the present, always with History and, even, with the European tradition.”
—Umberto Eco (b. 1932)
“We aspire to be something more than stupid and timid chattels, pretending to read history and our Bibles, but desecrating every house and every day we breathe in.”
—Henry David Thoreau (1817–1862)