We have developed a single-ended pulsed radiometry technique for the remote measurement of thermal diffusivity, absolute absorption coefficients, thickness, or layered structure of thin films, which can be free-standing or on a substrate. Our technique relies on the use of a short-pulsed N2 laser beam to heat up rapidly the sample surface (e.g., by a few degrees Celsius), and the detection of the shape of the transient IR thermal radiation that is backscattered from the sample surface. No sample damage occurs, since the laser pulse (< 1-mJ energy and 8-nsec duration) is gently focused to a spot size of ~4-mm diam at the sample. We have developed exact analytical solutions to permit us to analyze the observed IR signal profile to derive the desired parameters of the sample. We have applied this single-ended pulsed photothermal radiometry (PPTR) technique to various cases of metal films, polymer films, and paper (including paper currency) and have demonstrated several important advantages of the PPTR technique for material testing applications; namely, it is noncontact, fast, nondestructive, and applicable to materials with an inaccessible backside. This should be compared with traditional methods1 of measuring thermal diffusivity; these methods are usually double-ended (i.e., requiring transmission probing) or require the attachment of electrical or thermocouple leads to the sample.

© 1984 Optical Society of America

PDF Article
More Like This
Progress in surface photoacoustic wave spectroscopy of thin films

S. R. J. Brueck, Thomas F. Deutsch, and D. E. Oates
WD4 Conference on Lasers and Electro-Optics (CLEO) 1984

Excimer laser etching of polymeric films

P. E. Dyer and J. Sidhu
THK4 Conference on Lasers and Electro-Optics (CLEO) 1984

Determination of agar tissue phantoms depth profiles with pulsed photothermal radiometry

Matija Milanič, Boris Majaron, and J. Stuart Nelson
6631_49 European Conference on Biomedical Optics (ECBO) 2007


You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
Login to access OSA Member Subscription