Model for evaluating the effect of single-point diamond turning parameters on the diffraction efficiency and MTF of diffractive lenses

We present a mathematical model relating single-point diamond turning machining parameters to the optical performance of diffractive lenses. The theoretical surface error is decomposed into a turning-groove structure and an ideal diffractive structure containing transmission blockages. Combining scalar diffraction theory with the phase-delay model, the effects of the tool nose radius and feed rate on the diffraction efficiency, polychromatic integral diffraction efficiency, and modulation transfer function are analyzed. A case study of a single-layer diffractive optical element for a 3.4- to 4.9-μm continuous-zoom system validates the model, providing a theoretical basis for selecting initial machining parameters and improving fabrication efficiency.