An optimization method of rough surface adapted small rectangular LD laser source based on combination of Powell prism and cylindrical lenses

A combination optimization method was proposed to design a small-size rectangular laser spot and decrease the measurement error caused by the uneven intensity distribution of LD laser source. First, the intensity distribution of LD was analyzed and the combination lens structure of Powell prism and cylindrical lenses was proposed. The equations were established to calculate the profile parameters of lenses. And an illuminance loss model δΔED±R was built to determine the values of laser spot size, working reference and range. Secondly, the specific design process of our method was given, the 3D model was established and simulated in ZEMAX to further improve the imaging uniformity. Finally, the collimation, uniformity and location deviation of the spot were discussed. The average uniformity was 95.626%, and the difference of location deviation on shot peened surfaces was 0.004 μm in x direction and 0.121 μm in y direction when compared with the white ceramic surface.