TY - JOUR
T1 - Quenching of fluorescence by light
T2 - A new method to control the excited-state lifetimes and orientations of fluorophores
AU - Gryczynski, Ignacy
AU - Kuśba, Józef
AU - Bogdanov, Valery
AU - Lakowicz, Joseph R.
PY - 1994/3
Y1 - 1994/3
N2 - We report steady-state and time-resolved studies of quenching of fluorescence by light i.e. "light quenching." The dyes rhodamine B (RhB) and 4-dicyanomethylene-2-methyl-6(p-dimethamino)-4H-pyrane (DCM) were excited in the anti-Stokes region from 560 to 615 nm. At a high illumination power the intensities of DCM and RhB were sublinear with incident power, an effect we believe is due to stimulated emission, and not ground-state depopulation. The extent of light quenching was proportional to the amplitude of the emission spectrum at the incident wavelength, as expected for light-stimulated decay from the excited state. Control measurements at a decreased average illumination power, and in solvents of various viscosities, indicated that the effect was not due to undesired photochemical processes. Importantly, the frequency-domain intensity decays remained single exponentials, and the lifetimes were unchanged with light quenching, which suggests that the effect was not due to heating or other photochemical effects. These results are consistent with a quenching process which occurs within the quenching pulse. Importantly, as expected for light quenching with a single pulsed laser beam, the time 0 anisotropies of RhB and DCM were decreased due to orientation-dependent quenching of the excited-state population. In closing we discuss some possible future applications of light quenching to studies of dynamic processes.
AB - We report steady-state and time-resolved studies of quenching of fluorescence by light i.e. "light quenching." The dyes rhodamine B (RhB) and 4-dicyanomethylene-2-methyl-6(p-dimethamino)-4H-pyrane (DCM) were excited in the anti-Stokes region from 560 to 615 nm. At a high illumination power the intensities of DCM and RhB were sublinear with incident power, an effect we believe is due to stimulated emission, and not ground-state depopulation. The extent of light quenching was proportional to the amplitude of the emission spectrum at the incident wavelength, as expected for light-stimulated decay from the excited state. Control measurements at a decreased average illumination power, and in solvents of various viscosities, indicated that the effect was not due to undesired photochemical processes. Importantly, the frequency-domain intensity decays remained single exponentials, and the lifetimes were unchanged with light quenching, which suggests that the effect was not due to heating or other photochemical effects. These results are consistent with a quenching process which occurs within the quenching pulse. Importantly, as expected for light quenching with a single pulsed laser beam, the time 0 anisotropies of RhB and DCM were decreased due to orientation-dependent quenching of the excited-state population. In closing we discuss some possible future applications of light quenching to studies of dynamic processes.
KW - Light quenching
KW - excited-state lifetime
KW - fluorophores
UR - http://www.scopus.com/inward/record.url?scp=0038499630&partnerID=8YFLogxK
U2 - 10.1007/BF01876664
DO - 10.1007/BF01876664
M3 - Article
C2 - 24233304
AN - SCOPUS:0038499630
SN - 1053-0509
VL - 4
SP - 103
EP - 109
JO - Journal of Fluorescence
JF - Journal of Fluorescence
IS - 1
ER -