Measurements of Fluorescence Decay Time by the Frequency Domain Method

Abstract

Among the many contributions of Gregorio Weber to science and technology, the development of frequency domain technology in his lab in 1969 has caused a deep controversy, dividing scientists that will refuse using anything but the frequency domain approach to measure the fluorescence decay from the other camp that simply refuses anything but the time-correlated single photon counting (TCSPC) approach. Although at the time of the major contribution of Gregorio Weber and Richard Spencer in 1969, the TCSPC method was not yet invented, the basic controversy “frequency domain vs time domain” in the field continues today. We have made progress both in the scientific understanding and in describing the technical differences between the two approaches; still it is interesting how scientists continue to be divided. As for many of the contributions of Gregorio Weber that stirred controversy, I would like to mention a common theme of my conversations with Dr. Weber about refusing to follow a “god’ and about the independence of the scientific thinking from “common beliefs” that ultimately slows scientific progress. In this chapter I would like to describe the scientific progress brought about by Weber’s ideas in this specific “technological” area that should be judged by “pure” scientific analysis rather than by beliefs.