Harmonic Diffractive-Refractive F-theta Lens Used in Semiconductor Laser Drilling

Based on the wavelength range of semiconductor laser and the features of harmonic diffractive element (HDE), the design of a hybrid f-theta lens consisting of HDE was discussed. The HDE was introduced into the f-theta lens with semiconductor laser and Nd:YAG laser working on the wavelength range of 0.8~1.5 μm, and it shows that the monochromatic aberrations and chromatic aberrations have been rectified satisfactorily with simple optical materials. The system possesses the advantage of compact in structure with few elements. The modulation transfer function at each wavelength in the wavelength range of 0.8~1.5 μm approaches or attains the diffraction limit.