TY - JOUR
T1 - Theory of light quenching
T2 - effects of fluorescence polarization, intensity, and anisotropy decays
AU - Kuśba, J.
AU - Bogdanov, V.
AU - Gryczynski, I.
AU - Lakowicz, J. R.
N1 - Funding Information:
This work was supported by grants from the National Science Foundation (DIR-8710401 and BIR-9319032) and National Institutes of Health (BR-08119). J. R. Lakowicz expresses appreciation to the Medical Biotechnol- ogy Center at the University of Maryland at Baltimore.
PY - 1994
Y1 - 1994
N2 - Experimental studies have recently demonstrated that fluorescence emission can be quenched by laser light pulses from modern high repetition rate lasers, a phenomenon we call "light quenching." We now describe the theory of light quenching and some of its effects on the steady-state and time-resolved intensity and anisotropy decays of fluorophores. Light quenching can decrease or increase the steady-state or time-zero anisotropy. Remarkably, the light quenching can break the usual z axis symmetry of the excited-state population, and the emission polarization can range from -1 to +1 under selected conditions. The measured anisotropy (or polarization) depends upon whether the observation axis is parallel or perpendicular to the propagation direction of the light quenching beam. The effects of light quenching are different for a single pulse, which results in both excitation and quenching, as compared with a time-delayed quenching pulse. Time-delayed light quenching pulses can result in step-like changes in the time-dependent intensity or anisotropy and are predicted to cause oscillations in the frequency-domain intensity and anisotropy decays. The increasing availability of pulsed laser sources offers the opportunity for a new class of two-pulse or multiple-pulse experiments where the sample is prepared by an excitation pulse, the excited state population is modified by the quenching pulse(s), followed by time- or frequency-domain measurements of the resulting emission.
AB - Experimental studies have recently demonstrated that fluorescence emission can be quenched by laser light pulses from modern high repetition rate lasers, a phenomenon we call "light quenching." We now describe the theory of light quenching and some of its effects on the steady-state and time-resolved intensity and anisotropy decays of fluorophores. Light quenching can decrease or increase the steady-state or time-zero anisotropy. Remarkably, the light quenching can break the usual z axis symmetry of the excited-state population, and the emission polarization can range from -1 to +1 under selected conditions. The measured anisotropy (or polarization) depends upon whether the observation axis is parallel or perpendicular to the propagation direction of the light quenching beam. The effects of light quenching are different for a single pulse, which results in both excitation and quenching, as compared with a time-delayed quenching pulse. Time-delayed light quenching pulses can result in step-like changes in the time-dependent intensity or anisotropy and are predicted to cause oscillations in the frequency-domain intensity and anisotropy decays. The increasing availability of pulsed laser sources offers the opportunity for a new class of two-pulse or multiple-pulse experiments where the sample is prepared by an excitation pulse, the excited state population is modified by the quenching pulse(s), followed by time- or frequency-domain measurements of the resulting emission.
UR - http://www.scopus.com/inward/record.url?scp=0028029712&partnerID=8YFLogxK
U2 - 10.1016/S0006-3495(94)80686-1
DO - 10.1016/S0006-3495(94)80686-1
M3 - Article
C2 - 7858140
AN - SCOPUS:0028029712
SN - 0006-3495
VL - 67
SP - 2024
EP - 2040
JO - Biophysical Journal
JF - Biophysical Journal
IS - 5
ER -