Thermal wave imaging with phase sensitive modulated thermography

TLDR: In this paper, the authors combined thermal wave and thermography to provide a short-time low-frequency phase angle image where non-thermal features can be suppressed using lock-in data analysis.

Abstract: Thermography and thermal wave techniques can be combined to provide in a short‐time low‐frequency phase angle images where nonthermal features can be suppressed. The principle is optical thermal wave generation simultaneously on the whole sample surface and sequential monitoring of all pixels using both thermographic techniques and lock‐in data analysis. Due to parallel stationary excitation one can use low modulation frequencies allowing for a depth range that is of relevance for applications.