Conditions for optimum photothermal discrimination of subsurface thermal inhomogeneities U. Seidel, A. Glazov, K. Haupt, H.G. Walther, J. Burt, B.K. Bein and J. Pelzl J. Phys. IV France, 04 C7 (1994) C7-555-C7-558 DOI: 10.1051/jp4:19947130