= Fluorescence microscope
{wiki}
A <fluorescence microscope> maps <photon emission> to an image. Excitation <light> passes through a <fluorescence excitation filter> and reflects from a wavelength-selective <beam splitter> into the objective <optical lens>. Returning <fluorescence> passes through that <beam splitter> and a <fluorescence emission filter> to the <photodetector>. Rejecting excitation makes faint emission visible.<Advanced Fluorescence Microscopy Techniques—FRAP, FLIP, FLAP, FRET and FLIM by Hellen C. Ishikawa-Ankerhold and others>[§1.2.1, Figure 5 and excitation/emission-filter paragraphs]{ref}
An ordinary image records emission-band counts at each <pixel>. Adding pulse-delay measurements gives a <fluorescence lifetime> map; scanning emission <wavelength> gives spectral information instead. <Confocal microscopy> adds spatial rejection and <confocal optical sectioning>, as developed in its own branch. An unlabeled specimen under the same illumination reveals intrinsic <fluorescence> and excitation leakage; excitation-blocked frames reveal detector background. A blank cannot perfectly predict background in a differently prepared specimen.
Back to article page
