Study of photoacoustic phase spectrum of a double-layer film

Abstract

The photoacoustic (PA) spectrometry of a double-layer film sample was studied and an improved phase-resolved method was developed. Phase-resolved equations for different conditions were derived and were applied to plant leaf samples. For spinach and Chinese ilex leaf samples, the resolved outer layer and inner layer PA signals corresponded perfectly with the experimental PA signal for a single outer layer and inner layer. In addition, the depth profiling method was used to determine the thickness of the outer layer and PA absorptions of a single outer layer, and the results were also in agreement with those of the phase-resolved method applied to plant leaf samples.