Comparative investigation of the effect of heat and optical radiation on the structure of island metal films by optical fluctuation microscopy

Variations in the structural parameters of island sodium films on the quartz surface, caused by heating or exposure to optical radiation, are investigated by the optical method proposed earlier. A correct scheme of processing the measured data is developed. It is shown that to determine the structure parameters, the measurements of both the mean values and fluctuations of transmission and reflection coefficients of the film and of their correlator are required. It is also demonstrated that under a number of assumptions, it is possible to determine the character of the process of evaporation of islands and to reveal the evolution of the distribution function by using the data of measurements. It was found experimentally that variations in the structural parameters of a film during its evaporation caused by heating of the substrate or irradiation by light can noticeably differ. This fact is explained by a difference in the mechanisms of action of heating and irradiation on an island.