A 266-nm laser-induced fluorescence system was used to study the effect of polarization of the excitation source and geometry of the collection optics on the ratio of the signal from a fluorescence standard, quinine sulfate, and the Raman scatter from water. Although the ratio is sometimes considered to be a constant and is used for intersystem comparisons, our studies showed that the Raman signal and, thus, the ratio can vary by a factor of up to 3.6. These experimental values agree with previous studies by others involving gas and flame Raman spectroscopy and suggest a new calibration method for intersystem comparison of different fluorescence systems.
© 2003 Optical Society of America
(010.4450) Atmospheric and oceanic optics : Oceanic optics
(120.6200) Instrumentation, measurement, and metrology : Spectrometers and spectroscopic instrumentation
(280.3420) Remote sensing and sensors : Laser sensors
(300.2530) Spectroscopy : Fluorescence, laser-induced
(300.6450) Spectroscopy : Spectroscopy, Raman
Vasanthi Sivaprakasam and Dennis K. Killinger, "Effect of polarization and geometric factors on quantitative laser-induced fluorescence- to-Raman intensity ratios of water samples and a new calibration technique," J. Opt. Soc. Am. B 20, 1980-1989 (2003)