FLUX WAVES AND THE GENERATION OF PHOTOACOUSTIC SIGNALS

Abstract

It has been shown that thermal waves must be considered in order to adequately describe the generation of photoacoustic signals in condensed phases. A completely equivalent approach is provided by the corresponding energy flux waves, and the resulting energy considerations give valuable insights into the thermodynamic processes underlying the production of the acoustic signal. For example, it can be shown that the generation of an acoustic signal can be viewed as a perturbation to the thermal diffusion model; although this perturbation may be negligible for calls filled with a gas, it may not be negligible for cells filled with a liquid.