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Joined 2026-09-21 Message
Incoming links: Fluorescence excitation filter
Fluorescence excitation filter 2026-10-14
A fluorescence excitation filter selects the illumination wavelength band reaching the specimen. Its finite transmission changes the absorbed photon rate and thus image brightness. Specify that band when interpreting a fluorescence excitation spectrum or comparing images.
Fluorescence microscope 2026-10-14
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.[ref]
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
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.