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Same region showing Chlorophyll A autofluorescence with 440 nm laser excitation and far red emission (below). Microscopic images of a moss leaf from Plagiomnium undulatum. Bright-field microscopy at the top and fluorescence microscopy at the bottom. The red fluorescence is from the chlorophyll in the chloroplasts.
Many types of calcite and amber will fluoresce under shortwave UV, longwave UV and visible light. Rubies, emeralds, and diamonds exhibit red fluorescence under long-wave UV, blue and sometimes green light; diamonds also emit light under X-ray radiation. Fluorescence in minerals is caused by a wide range of activators. In some cases, the ...
Electrons change energy states by either resonantly gaining energy from absorption of a photon or losing energy by emitting photons. In chemistry-related disciplines, one often distinguishes between fluorescence and phosphorescence. The former is typically a fast process, yet some amount of the original energy is dissipated so that re-emitted ...
Atomic Fluorescence Spectroscopy (AFS) techniques are useful in other kinds of analysis/measurement of a compound present in air or water, or other media, such as CVAFS which is used for heavy metals detection, such as mercury. Fluorescence can also be used to redirect photons, see fluorescent solar collector.
A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light.
Fluorescence of different substances under UV light. Green is a fluorescein, red is Rhodamine B, yellow is Rhodamine 6G, blue is quinine, purple is a mixture of quinine and rhodamine 6g. Solutions are about 0.001% concentration in water. Fluorophore molecules could be either utilized alone, or serve as a fluorescent motif of a functional system.
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The traditional fluorescence-based imaging is unfortunately faced with challenges such as low tissue penetration and background autofluorescence. [20] Upconversion (UC)-based bioimaging can overcome these limitations as their excitation occurs at lower frequencies and the emission at higher frequencies.