Concentration depolarization of fluorescence in excitation by intense light fluxes

Воропай, Е. С.; Gaisenok, V. A.; Dudarev, I. A.; Kolev, Ivan; Sarzhevskii, A. M.

doi:10.1007/bf00606951

Cited by 3 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Principally circularly polarized light can affect FRET at two levels: (i) “passively” at the level of photoselection of the donors via widening the orientational distribution of excited donors (i-a) , and the “homo-FRET frustration relief” effect (i-b) − and (ii) “actively” also at the level of the donor’s excited state via enhancing local fluctuations via angular momentum transfer. − (i-a) Widening of orientational distributions of excited donors …”

Section: Discussionmentioning

confidence: 99%

“…In contrast, if the excitation is depolarized, that is, random, assuming all orientations in plane, than for each excited donor orientation, a matching acceptor orientation could be found for which the FRET rate is the highest (Figure Panel B). As a hint on this “homo-FRET frustration” (as another type of “orientation mismatch”) effect, earlier we observed modulation of homo-FRET via changing the intensity of exciting light, far before reaching saturation. − For the active mechanism, way (ii), please see the paragraph “FRET in helical light” in the Discussion.…”

Section: Introductionmentioning

confidence: 89%

See 1 more Smart Citation

Fluorescence Resonance Energy Transfer Gating by Elliptically Polarized Light on the Cell Surface

et al. 2021

View full text Add to dashboard Cite

Enhancements of hetero-fluorescence resonance energy transfer (FRET) and homo-FRET have been observed upon excitation with circularly polarized light as compared to excitation with the linearly polarized one in the context of fluorescent dye-labeled cell surface receptors. The enhancement effect has been gradually evolved with changing ellipticity of the exciting light from zero of the linearly polarized light to unity of the circularly polarized one. The measurements have been carried out in a single-laser dual-anisotropy scheme in a flow cytometer, where polarized intensity components in the donor and acceptor channels have been measured simultaneously. For hetero-FRET, the FRET-enhancement effect revealed by a combined detection of donor quenching and sensitized emission of the acceptor has been corroborated by a parallel increase in donor anisotropy and a decrease in acceptor anisotropy. As to homo-FRET, the FRET enhancement, inferred from increased depolarizations of anisotropies measured in two different emission bands, centered at a shorter and a longer wavelength, has also been corroborated by a parallel reduction in “the longer to shorter wavelength” anisotropy ratio. The observed enhancement effects are explained by a relief of orientation mismatch between the FRET donors and acceptors, a phenomenon observable when excitation is depolarized as compared to the linearly polarized one, and a concomitant “homo-FRET-amplified hetero-FRET” phenomenon, both based on an increase in the orientation factor (κ2) for FRET. Circularly polarized light represents a depolarized mode of excitation leading to a photoselected orientational distribution of the donors matching better with that of the potential acceptors. The magnitude of this effect is dictated by the anisotropy of the orientational distributions of the donor and the acceptor. By comparing FRET with excitations of different helicities, a new steady-state method for the detection of molecular dynamics is presented. The method can equally be used in flow cytometers and fluorescence microscopes equipped with excitation with helical light even when the detection is not polarized. The conventional formalism of anisotropy detection in the T-format at vertically polarized excitation has been extended to linearly polarized excitation at different polarization angles and depolarized excitations.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

Fluorescence Resonance Energy Transfer Gating by Elliptically Polarized Light on the Cell Surface

et al. 2021

View full text Add to dashboard Cite

show abstract

“…37 In a series of measurements the Russian spectroscopists have studied light quenching and its effect on the emission spectra and depolarization of fluorophores. [38][39][40] These measurements were performed with long laser pulses resulting in essentially steady-state light quenching. With one exception, 41 there have been no direct measurements of changes in the intensity decays of fluorophores under pulsed illumination.…”

Section: Discussionmentioning

confidence: 99%

Light Quenching of Fluorescence Using Time-Delayed Laser Pulses As Observed by Frequency-Domain Fluorometry

Gryczyński¹,

Kuśba²,

Lakowicz³

1994

J. Phys. Chem.

View full text Add to dashboard Cite

We describe experimental observations of fluorescence quenching by time-delayed light pulses whose wavelength overlaps the emission spectrum of 4-(dimethylamino)-4'-cyanostilbene (DCS). The relative cross sections for light quenching were proportional to the amplitude of the emission spectra at the light quenching wavelength.The frequency-domain intensity and anisotropy decay measurements showed oscillations resulting from timedelayed light quenching. The amplitude of the oscillations depends upon the amount of light quenching. The frequency of the oscillations depends upon the delay between the excitation and quenching pulses. To the best of our knowledge, only a stepwise decrease in the intensity or anisotropy could produce such oscillations in the frequency-domain data. Light quenching of fluorescence is thus shown to provide a means to control the number and orientation of the excited fluorophores. The use of multiple light pulses for excitation and quenching can have far-reaching applications in the use of time-resolved fluorescence in physical chemistry and biophysics. IntroductionModern pulsed laser light sources and high-speed detectors have resulted in remarkable sensitive and resolution of timedependent processes.14 With the exception of pumpprobe and up-conversion measurement^,^ most studies of time-resolved fluorescence use the picosecond or femtosecond laser pulses only for excitation but do not take advantage of the opportunities available created by the temporarily intense illumination. This situation is now changing, as seen by the recent reports on the effects of intense illumination on the ground-state fluorophore

show abstract

“…According to [6], the probability of NEET is proportional to the integral of the overlapping of the absorption spectrum of the energy acceptor and luminescence spectrum of its donor. Consequently, upon excitation of any molecule the energy will migrate from it predominantly to the moleculesacceptors that have a lower frequency of the 0-0 transition.…”

mentioning

confidence: 99%

Influence of nonradiative excitation-energy transfer on the dye laser active-medium gain-coefficient dichroism

Klishchenko

Kozlov

2005

J Appl Spectrosc

View full text Add to dashboard Cite

The excitation power dependences of the luminescence polarization degree and of the anisotropy of the stimulated emission from glycerin solutions of rhodamine 6G at different dye concentrations have been obtained experimentally. It is shown that the anisotropy of the stimulated emission is determined by the dichroism of induced absorption in the range of low concentrations and by the development of excitation-energy migration into the generation channel. The complex character of the behavior of the fluorescence polarization degree is explained by the competition between several processes of excitation-energy transformation -nonradiative energy transfer and directed energy transfer to excimers with an increase in the dye concentration and in the excitation power.Introduction. In a number of theoretical and experimental works [1][2][3][4], the anisotropy of emission from liquid dye lasers depending on the active substance concentration was investigated. The dependences of laser-radiation polarization for a wide range of concentrations were obtained. It was found that in polarized radiation pumping the concentration of solutions exerted an appreciable effect on the polarization degree and effectiveness of generation. The greatest generation effectiveness, to which the smallest value of the polarization degree corresponded, was reached at a certain concentration. Upon increase or decrease of concentration, along with a decrease in the effectiveness of transformation of the excitation energy into the energy of generation, one observes an increase in the degree of polarization of generation radiation up to unity, which in [1] is attributed to competition between gain and losses in the cavity. In [4], these dependences were interpreted by the different contribution of mutually perpendicular polarization modes due to nonradiative excitation-energy transfer (NEET). Therefore, to obtain complete clarity in the explanation of this effect additional experimental investigations of the dependence of the laser-radiation anisotropy on the concentration of an active substance in a solution were required. In the present work, we investigate the dependence of the luminescence anisotropy and generation of concentrated solutions of rhodamine 6G in glycerin on excitation power. Measurement Procedure. Excitation of luminescence and of solution generation was made by the second harmonic of a YAG-Nd laser (LF-116, "Solar", Belarus) with a wavelength of λ = 532 nm into the first absorption band of the rhodamine 6G dye in an orthogonal variant of pumping.The polarized radiation of the second harmonic of pulsed laser 1 (Fig. 1) with a pulse repetition rate of 10 Hz and duration of a single pulse of 10 nsec was transformed with the aid of a half-wave plate 2 into polarized radiation with a prescribed polarization vector and was used to excite the luminescence of glycerin solutions of rhodamine 6G (3). The luminescence emitted by the dye was spatially divided by a Wallaston prism 4 into two components with mutually perpendicular polarizations...

show abstract

Concentration depolarization of fluorescence in excitation by intense light fluxes

Cited by 3 publications

References 4 publications

Fluorescence Resonance Energy Transfer Gating by Elliptically Polarized Light on the Cell Surface

Fluorescence Resonance Energy Transfer Gating by Elliptically Polarized Light on the Cell Surface

Light Quenching of Fluorescence Using Time-Delayed Laser Pulses As Observed by Frequency-Domain Fluorometry

Influence of nonradiative excitation-energy transfer on the dye laser active-medium gain-coefficient dichroism

Contact Info

Product

Resources

About