Purely thermal-wave photopyroelectric interferometry

A thermal-wave interferometric technique based on pure thermal-wave interference using two-cavity photopyroelectric (PPE) detection has been developed. The salient features of this interferometry are investigated with a general theory, which describes the dependence of the PPE signal on the optical, thermal, and geometric parameters of the thermal-wave cavity configuration. Preliminary experimental results are presented. A major feature of the technique is the efficient suppression of the background PPE signal base line. The physical origins of the interferometry are also discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)02811-X].