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Resultingly, only a small percentage of the excitation light reaches the fluorophores that are visible for the detection system. The inner filter effects change the spectrum and intensity of the emitted light and they must therefore be considered when analysing the emission spectrum of fluorescent light. [5] [10]
The spectrum of light emitted from a fluorescent lamp is the combination of light directly emitted by the mercury vapor, and light emitted by the phosphorescent coating. The spectral lines from the mercury emission and the phosphorescence effect give a combined spectral distribution of light that is different from those produced by incandescent ...
When the molecule returns to the ground state, it releases a photon, which is the fluorescent emission. The excited state lifetime is short, so emission of light is typically only observable when the absorbing light is on. Fluorescence can be of any wavelength but is often more significant when emitted photons are in the visible spectrum.
The emission spectrum is usually sharper than the excitation spectrum, and it is of a longer wavelength and correspondingly lower energy. Excitation energies range from ultraviolet through the visible spectrum, and emission energies may continue from visible light into the near infrared region. The main characteristics of fluorophores are:
The emission is collected at the perpendicular to the emitted light. The emission is also either passed through a filter or a monochromator before being detected by a photomultiplier tube, photodiode, or charge-coupled device detector. The signal can either be processed as digital or analog output.
F7–F9 are "broadband" (full-spectrum light) fluorescent lamps with multiple phosphors, and higher CRIs. Finally, F10–F12 are narrow triband illuminants consisting of three "narrowband" emissions (caused by ternary compositions of rare-earth phosphors) in the R,G,B regions of the visible spectrum.
The fluorescence of this molecule is very intense; peak excitation occurs at 495 nm and peak emission at 520 nm. Values for the deprotonated form in basic solution. [citation needed] Fluorescein has a pK a of 6.4, [2] and its ionization equilibrium leads to pH-dependent absorption and emission over the range of 5 to 9. Also, the fluorescence ...
DyLight Fluors have comparable excitation and emission spectra and are claimed to be more photostable, brighter, and less pH-sensitive. The excitation and emission spectra of the DyLight Fluor series cover much of the visible spectrum and extend into the infrared region, allowing detection using most fluorescence microscopes, as well as ...