A fundamentally new method for measuring optical coupling coefficients is described. A sample of a particular shape is subjected to a fixed tensile load and heated with pulsed optical radiation. The resulting peak tensile relaxation is proportional to the total absorbed energy; evolution of the coupling coefficient may thus be observed. A prototype system was constructed, and coupling coefficients were measured as a function of incident energy for CO2 laser pulses on bare and painted aluminum surfaces. With a sample of known absorptance and thermal properties, the system functions as a sensitive, fast-response, absolute-energy-measurement device.
© 1981 Optical Society of America
Original Manuscript: September 14, 1981
Published: December 1, 1981
S. C. Seitel, J. O. Porteus, and W. N. Faith, "Measurement of optical coupling coefficients based on thermal expansion," Opt. Lett. 6, 619-621 (1981)