Effects of polarization on laser diffusion and materials modification

Laser diffusion has been widely used to modify the metallurgical composition at the surface of materials for improving the mechanical, optical and electromagnetic properties. In order to have a uniform heating for the substrates, a beam shaping lens is designed for transforming a Gaussian laser beam to a flat-top laser beam. Pt atoms have been incorporated into Ti and Ta sheets and the transmitted magnetic field (63.86 MHz) strengths are measured to determine the transmittance of the samples. The treated Ti samples have lower transmittance than the as-received Ti samples due to increased electrical conductivity. The treated Ta samples, on the other hand, have higher transmittance than the as-received Ta samples due to reduced electrical conductivity. The increased electrical conductivity may be due to the diffused Pt atoms and the decreased electrical conductivity may be due to the increased oxygen atoms. Regarding the polarization effect, the samples irradiated by linearly polarized laser beam have higher Pt concentration and exhibit more changes in the transmittance.