LIF Spectroscopy of Fruits: Study of Excitation Wavelength Independence

In fluorescence spectroscopy, fluorescence emissiongenerally occurs from the excited state with the lowest energy. This is known as “Kasha’s rule” and is a general principle with only a few rare exceptions. As a consequence,the emission wavelength is independent of the excitation wavelength. In order to select an appropriate excitation source in fluorescence spectroscopy,it is very important to know the relation between the excitation source wavelength and the emission wavelength. The aim of this paper isto study the excitation-wavelength-independent fluorescence emission of some fruits. To do so, a fluorescence spectrometer controlled by labVIEW software was developed forcollecting the fluorescence spectra ofsome famous fruits.A semiconductor laser and light emitting diodes with different wavelengths was used as the excitation sources.