The mirage-effect/thermal wave technique as a modern technique for thermal property characterization is described. In this technique, the thermal diffusivity of a material is determined by measuring the time and space varying temperature distribution (thermal wave) in the material generated by a intensity modulated heating laser beam. These thermal waves, whose propagating features are directly related to the thermal properties of the material, are detected through the deflection of a probe laser beam due to modulation of gradient of the index of refraction (mirage effect) either in the air above the specimen (the in-air technique) or in the specimen itself (the in-solid technique). Three-dimensional theories, for both in-air and in-solid mirage techniques, are represented. In order to extract the material parameters by comparing the theory with experimental data, an extensive data analysis procedure based on multiparameter-least-squares has been developed. The experimental and data analysis details are discussed. Topics concerned with the quality and reliability of the measurements are addressed.;This technique has been successfully applied to the thermal property characterization of single crystal diamond with varying isotope contents. The results showed a 50% enhancement in the thermal conductivity by removal of C
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