New method for the simultaneous measurement of fluorescence and phosphorescence depolarizations

Liqun Yang; Daniel McStay; Abhay Sharma; Peter J. Quinn; Alan J. Rogers

doi:10.1117/12.58220

1 April 1992 New method for the simultaneous measurement of fluorescence and phosphorescence depolarizations

Liqun Yang, Daniel McStay, Abhay Sharma, Peter J. Quinn, Alan J. Rogers

Proceedings Volume 1640, Time-Resolved Laser Spectroscopy in Biochemistry III; (1992) https://doi.org/10.1117/12.58220
Event: OE/LASE '92, 1992, Los Angeles, CA, United States

Abstract

A new technique for the simultaneous measurement of fluorescence and phosphorescence depolarization is reported. The technique is based on a newly developed photomultiplier gain suppression technique. The gain suppression characteristics of the circuit were studied by applying a constant level of incident light. To demonstrate this new technique, a solid sample of the triplet probe eosin was excited by a pulsed, frequency doubled Nd:YAG laser; the resulting orthogonally-polarized emissions were collected by two balanced photomultiplier (PMTs). The gains of the PMTs were suppressed for the duration of the fluorescence emission, and subsequently returned to normal, in order to keep the measured fluorescence and phosphorescence signals at the same level. The suppression of the gain was controlled by using a specially designed dual-channel PMT gain suppression circuit. The signals from the PMTs were recorded by two digital oscilloscopes, one set at a fast sweep time in order to measure the transient fluorescence depolarization and the other set at a slow sweep time in order to measure the slow phosphorescence depolarization. The anisotropies can then be deduced from the two sets of recordings.

Citation Download Citation

Liqun Yang, Daniel McStay, Abhay Sharma, Peter J. Quinn, and Alan J. Rogers "New method for the simultaneous measurement of fluorescence and phosphorescence depolarizations", Proc. SPIE 1640, Time-Resolved Laser Spectroscopy in Biochemistry III, (1 April 1992); https://doi.org/10.1117/12.58220

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