A novel beam shaping optics, LSV (Linear-Polarized Shape Variable) optics, was developed, which provides a beam spot with variable aspect ratio, negligible shaping loss and high metallic absorptivity without absorption coating. The beam shaping properties of LSV optics for CO2 laser was analysed theoretically and experimentally in terms of intensity distribution, shaping efficiency and influence of misalignment. LSV optics was applied to transformation hardening, joining fine ceramics including Si3N4 and SiC and splitting laser beam as well. At 3 kW power level, case depth deeper than 2mm with 15mm width was attained without absorption coating in Ar atmosphere, and the case depth was varied from zero to 2.5 mm with keeping surface temperature at optimum value. Si3N4 and SiC ceramics were locally heated up to 1300 °C without any cracks, and were joined without preheating in 20 sec with insertion of Al-foil, providing bending strength as high as 500 MPa. Laser beam was split into nineteen spots with equal intensity by utilizing the interference of the laser beam.

Topics
Laser physics, Carbides, Chemical compounds, Ceramics
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© 1993 Laser Institute of America.
1993
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