ABSTRACT
Fluorescence microscopy is much more sensitive and selective than transmission microscopy. Robert Hooke published Micrographia in 1665, which contained a number of observations of the microscopic world using a primitive compound microscope. The “optical” or visible wavelengths of light form a narrow range, extending from approximately 400 to 750 nm, defined purely anthropogenically as the wavelengths that the human eye can see. The dichotomy of the two descriptions of light was the source of enormous debate for the first part of the 20th century and eventually united in quantum mechanics. Luminescence is the emission of light that occurs when an electron relaxes from a higher to lower electronic state. The difference between the peak of the absorption spectrum and the peak of the emission spectrum is called the Stokes shift. Static quenching occurs when the quencher molecule forms a complex with the fluorophore. Photobleaching is usually an irreversible process, leading to lowered fluorescence emission intensity.
