A computer generated hologram (CGH) has been developed for laser transformation hardening with a fiber-coupled high-power diode laser (HPDL). The laser beam shaped with the CGH is purposely non-uniform in order to obtain uniform depth of the hardened profile. The optimum intensity distribution of laser beam has been determined with the numerical simulation of dynamic thermal analysis based on the finite element method. A binary phase CGH of silica glass was designed and fabricated to realize the optimized intensity distribution of laser beam. When a steel plate surface was hardened by the 330W laser beam with the fabricated CGH, the cross-sectional hardened profile had a uniform depth, compared with experimental results for a defocused Gaussian beam and a flat-top shaped beam.

Topics
Gaussian beam, Holography, Lasers, Glass, Thermal analysis, Finite-element analysis
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© 2008 Laser Institute of America.
2008
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