Application of argon laser beam diffraction for determination of the properties of photoinduced processes in dyed PVA foils

摘要

It is shwon that far field patterns of argon laser beam interacting with dyed foil of polyvinyl alcohol (PVA) provide inforamtion on the mechanism of local foil discoloration or at least on a few properties of this process. In particular far field patterns observations allow discernment if the process is reversible (or a superposition of reversible and irreversible processes), photohtermal, photochemical or produce a stretching in sample (photoizomerisation). The effect was studied in PVA foil containing methyl red, photosynthetic bacteria, their fragments and pigments. Apart from indicating the possibility of using the far field patterns for discernment of the foil discoloration mechanisms, the results reported point to the perspectives of using the foil for laser beam modification, shift or modulation, as well as elements of optical memory.