SENSITIVE INTERFEROMETRIC VIDEO THERMAL-WAVE IMAGER

A new method of parallel thermal wave imaging is demonstrated in which the thermal wave image of a heated sample is converted into an optica l phase image which is sensitively probed by a Twyman-Green interferom eter. The sample is mounted onto an assembly of optical layers which a cts as a temperature sensitive mirror. Heat conduction from the sample to this mirror results in a two-dimensional distribution of optical p hase which is probed broadfield by the interferometer. The resulting t ransmission thermal wave image has characteristics analogous to those of photopyroelectric images. The interferogram produced in the interfe rometer may be recorded by videography, although rapid frame processin g methods will be required for the full advantages of the method to be realized. (C) 1996 American Institute of Physics.