Noncontact photopyroelectric (PPE) method for the thermo-optical characterisation of layered samples
Jean-Stéphane Antoniow, Jean-François Henry, Michel Egée, Mihai Chirtoc
A noncontact photopyroelectric (PPE) detection system has been used in order to investigate the thermo-optical properties of a multilayer structure, including an air gap between sample and pyroelectric sensor. The influence of the air layer on the PPE signal is discussed for a configuration with a laser beam to develop well-defined heat sources in the layers. The modulated thermal transfer phenomena are described by a two-dimensional model with axial symmetry, in a wide frequency bandwidth. The noncontact PPE method is applied to characterise the migration of fatty acid esters marked with a dye in thin PVC samples with a spatial resolution of a few micrometres.