Original sentence: Some protein or small molecules in cells are naturally fluorescent, this is called intrinsic or autofluorescence (such as NADH, tryptophan or green fluorescent protein), alternatively  specific or general protein, nucleic acids, lipids or small molecules can be "labelled" with a extrinsic fluorophore, a fluorescent dye which can be a small molecule, protein or quantum dot.fluorescence Anisotropy.fluorescent lifetime imaging.multiphoton exitation
Edited sentence: Measures the scattering of a fluorescent moiety.Multiphoton excitation is a way of focusing the viewing plane of the microscope by taking advantage of the phenomenon where two simultaneous low energy photons are absorbed by a fluorescent moiety which normally absorbs one photon with double their individual energy: say two NIR photons (800nm) to excite a UV dye (400nm).Some protein or small molecules in cells are naturally fluorescent, this is called intrinsic or autofluorescence (such as NADH, tryptophan or endogenous Phycoerythrin or green fluorescent protein), alternatively  specific or general protein, nucleic acids, lipids or small molecules can be "labelled" with a extrinsic fluorophore, a fluorescent dye which can be a small molecule, protein or quantum dot.Time-Resolved imagining or measurements measure the time taken by the fluorescent moiety to emit the absorbed energy after absorbing energy from nanosecond light pulses