Absolutely interferometric calibration of phase liquid crystal spatial light modulators using honeycomb gratings composited with Billet-split Fresnel zone plates.

The traditional interferometric calibration of phase spatial light modulators (SLM) based on interference fringes shift is easily disturbed due to environmental vibration. Here a kind of absolutely interferometric calibration of phase SLM is investigated to eliminate the disturbance using dual honeycomb gratings composited with Billet-split Fresnel zone plates (BsFZP), in which honeycomb gratings split an incident beam into three beams and the first two beams are interfered by BsFZP while the last beam is chosen as the absolute reference point. The experiments on both 532 and 632.8 nm incident wavelengths were separately carried out, and the measuring accuracy was proved by a SID4 wavefront sensor. The proposed high-accuracy calibration provided the basis for SLM application scenarios with high precision.