激光测头光束质量分析与控制

Quality analysis and control on beam of light in laser measuring probe

建立了光束质量控制的数学模型,提出了一种可定量评价光束质量的参数优化选择方法。针对激光测头进行了两片式光束质量控制光学系统的优化设计,并与光束聚焦控制、准直控制方法进行对比实验。激光结果证明:该优化光束控制系统在测量范围内既保持了光束的均匀性,光斑尺寸较小(光腰尺寸为34μm),又保证了光束的精细度,有效地抑制了光束质量引入的测量误差,在±5 mm测量范围内,其均方根误差仅为6.3μm,测量精度明显优于聚焦控制和准直控制系统。

A math model of beam quality control has been established and the beam quality evaluation parameter is presented. A dual-lenses beam quality optimized optical system has been designed for the small measuring probe. It not only keeps beam uniformity but also guarantees the refinement of laser beam, so that the positioning error caused by laser beam can be restrained effectively. Experiments show its feasibility. The beam quality controlled by the optimized system, whose RMS error is only 6.3 um at its measuring range within positive and negative 5 mm, is superior to those controlled by the focalized and collimated system.