Design of a hybrid diffractive/refractive achromatized telecentric f·θ lens

Abstract The design of a hybrid diffractive/refractive achromatized telecentric f · θ lens with a field of view (FOV) 50° and an effective focal length of 750 mm is presented. The optical stop is placed at the front focal plane so that it is a telecentric system. The design is based on a traditional refractive counterpart, and the designed system consists of a hybrid diffractive/refractive lens and four refractive lenses. The designed f · θ lens shows a considerable reduction in weight with a simplified structure, and exhibits superior performance compared to the refractive system. It is emphasized that the designed f · θ lens can be applied to modern color scanning systems that operate in the visible wavelength range with high performance. It can also be applied to high-energy scanning systems. When applying the designed hybrid diffractive/refractive f · θ lens to the high-energy scanning system, a big laser operating in one longitudinal mode can be replaced by a small multi-mode laser, and the scanning system can be simplified greatly with the accuracy improved.