Product Code: ICA12_M1006

Effects of Polarization on Laser Diffusion and Materials Modification
Authors:
Sen-Yong Chen, Laser-Advanced Materials Processing Laboratory CREOL, College of Optics and Photonics, Univ. of Central Florida; Orlando FL USA
Othmane Benafan, NASA Glenn Research Center, Structures and Materials Division; -
Aravinda Kar, Laser-Advanced Materials Processing Laboratory CREOL, College of Optics and Photonics, Univ. of Central Florida; Orlando FL USA
Raj Vaidyanathan, Advanced Materials Processing and Analysis Center (AMPAC), Mechanical, Materials, and Aerospace Engineering, Univ. of Central Florida; Orlando FL USA
Presented at ICALEO 2012

Laser diffusion of species into substrates allows creating desired surface properties with minimal changes in the surface chemistry. The effect of laser polarization on diffusion and the modification of electromagnetic properties are the primary focus of this study. Laser beams of different polarizations have been used to diffuse Pt into two types of substrates, titanium and tantalum, and the concentrations of Pt and oxygen are measured using Energy Dispersive X-Ray Spectroscopy. The transmitted magnetic field strength and electrical conductivity of samples are also measured. Higher Pt concentration was observed due to higher surface temperature and longer diffusion time at lower laser scanning speeds than at higher laser scanning speeds. Additionally the Pt concentration was slightly higher in the samples that were treated with a linearly polarized laser beam. This effect of polarization might be due to the synchronized oscillation of the laser electric field that controls the motion of the diffusing atoms in a particular direction. The concentrations of Pt and oxygen affect the electrical conductivity and magnetic transmittance of the substrates. For Ti samples, higher Pt concentration increases the electrical conductivity, resulting in lower transmittance. For Ta samples, on the other hand, higher oxygen concentration was observed that resulted in lower electrical conductivity and higher magnetic transmittance.