Wave-front Correction of Single-mode Laser Diode for Precise Focusing

Abstract

For the purpose to use a laser diode (LD) for direct material processing, the wave-front of a single-mode LD have been measured and corrected. The wave-front of the output beam of 0.1 W LD at 940 nm wavelength through a newly designed collimator lens was measured, and the wave-front error of about 1λ was corrected by the Laser Ablative Shaping (LAS) method. After 2 times of wave-front correction, the residual wave-front error was reduced to better than λ/4. The output beam was focused on to the plastic plates to make micro-marking for production tracing.