Surface wave propagation in an elastic laser-excited half-space with small-scale effects

The propagation of Rayleigh waves in an isotopic elastic half-space with small length scale effects whose surface is free from stress and subjected to laser irradiation is investigated. Using the nonlocal form of constitutive equations the balance of moment and laser-induced defect-concentration field equations are obtained. The frequency equation that governs the Rayleigh surface wave propagation in the considered medium has been derived. It is observed that the waves are dispersive in nature and that the dispersion is caused by the atomic defect generation. An approximate procedure is applied to obtain explicit expressions for phase velocity and attenuation (amplification) coefficients which characterize surface waves. It is shown that if the pump parameter is above the critical value, due to concentration-elastic instability coupled strain-defect nanosized ordered structures on the surface of solids arises. The period of these structures is proportional to the characteristic length of defect-atom interaction and increases with the increase of the temperature of the medium. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim