Abstract：
: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." In this overview article, we describe the possible effects of light quenching on the steady-state and time-resolved intensity and anisotropy of fluorophores. One can imagine two classes of experiments. Light quenching can occur within the single excitation pulse, or light quenching can be accomplished with a second time-delayed quenching pulse. The extent of light quenching depends on the amplitude of the emission spectrum at the quenching wavelength. Different effects are expected for light quenching by a single laser beam (within a single laser pulse) or for a time-delayed quenching pulse. Depending upon the polarization of the light quenching beam, light quenching can decrease or increase the anisotropy. Remarkably, the light quenching can break the usual z-axis symmetry of the excited state population, and 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 polarization can increase to unity under selected conditions. Quenching with time-delayed light pulses can result in step changes in the intensity or anisotropy, which is predicted to result in oscillations in the frequency-domain intensity and anisotropy decays. These predicted effects of light quenching, including oscillations in the frequency-domain data, were demonstrated to occur using selected fluorophores. The increasing availability and use of pulsed laser sources requires consideration of the possible effects of light quenching and offers the opportunity for a new class of two-pulse or multiple-pulse time-resolved experiments where the sample is prepared by the excitation pulse and subsequent quenching pulses to modify the excited state population, followed by time- or frequency-domain measurement of the optically prepared excited fluorophores.
journal_name
Photochem Photobioljournal_title
Photochemistry and photobiologyauthors
Lakowicz JR,Gryczyński I,Kuśba J,Bogdanov Vdoi
10.1111/j.1751-1097.1994.tb05147.xsubject
Has Abstractpub_date
1994-12-01 00:00:00pages
546-62issue
6eissn
0031-8655issn
1751-1097journal_volume
60pub_type
杂志文章abstract：:The retina and retinal pigment epithelium contain a number of retinoids in a metabolic pathway that eventually forms the visual pigments. This study investigates the photochemistry of those retinoids that may contribute to light-induced damage to the retina. These include retinal (RAL), retinol (ROL), retinylpalmitate...
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