Sensitivity of biphotonic systems to light intensity fluctuations: Experimental evidence in the thermoluminescence of fluoresceine in boric acid glass

We study the response of biphotonic systems to fluctuations of the incident light intensity. A convenient experimental model for such a system is the thermoluminescence of fluoresceine in boric acid glass. The location of the steady states of this system as a function of the incident light intensity is determined for constant and fluctuating modes of illumination. A comparison of the results for these two modes reveals that the light intensity fluctuations can significantly modify the curve of the steady states. For low values of the average intensity the efficiency of the photoionization is lowered, whereas for high values of the average light intensity the efficiency is enhanced