Off-Axis Wavefront Measurement System for Aspheres Based on a Reflective SLM

Reflective SLMs are gaining increasing attention for aspherical surface testing due to their dynamic adjustability, fast operation, and high optical efficiency, offering clear advantages over costly CGH methods. This paper presents a wavefront measurement system that avoids the need for dedicated beam-splitting or complex long optical paths typically required when using a reflective SLM in the interference section. The measured results are comparable to those obtained with a commercial lens compensation method, with the overall RMS values agreeing to within approximately 0.01λ, and the maximum RMS deviation from the mean remaining within 0.025λ across all temperature conditions. With its simple structure and short optical path, the system enables fast measurement.