The resolution of thermal profiling techniques

Mathematically, the determination of a polarization profile from pyroelectric data measured by the Laser Intensity Modulation Method (LIMM) or Laser Induced Thermal Pulse (LITP) is an ill-posed problem. This means that a variety of very different polarization profiles can be found which are all consistent with the experimental data. A common rule which avoids artifacts is to choose the smoothest profile (the principle of parsimony). Thereby, however, structures can be lost which may actually be contained in the experimental data. An optimum evaluation which extracts all the structures of a polarization profile which are significantly supported by the experimental data but which avoids the creation of artifacts requires to know the resolution of the thermal profiling techniques. Starting from the propagation properties of thermal waves and using a partial deconvolution this resolution has been derived. It is given in dependence of the precision of the experimental data and the frequency range of the experiment.