Dong Xuelin, Feng Xue, Hwang Keh-Chih, Ma Shaopeng, Ma Qinwei
AML, Department of Engineering Mechanics, Tsinghua University, Beijing, China.
Opt Express. 2011 Jul 4;19(14):13201-8. doi: 10.1364/OE.19.013201.
Coherent gradient sensing (CGS), a shear interferometry method, is developed to measure the full-field curvatures of a film/substrate system at high temperature. We obtain the relationship between an interferogram phase and specimen topography, accounting for temperature effect. The self-interference of CGS combined with designed setup can reduce the air effect. The full-field phases can be extracted by fast Fourier transform. Both nonuniform thin-film stresses and interfacial stresses are obtained by the extended Stoney's formula. The evolution of thermo-stresses verifies the feasibility of the proposed interferometry method and implies the "nonlocal" effect featured by the experimental results.
