Fast and high-resolution polarization error test of large aperture optics using polarization-tunable interferometric...

As optical systems evolve toward larger apertures, higher precision, and broader frequency bands, sub-nanometer accuracy and sub-millimeter resolution residual birefringence metrology play a crucial role in the preparation and manufacturing of large-aperture optical materials. Traditionally, polarization errors in optical elements are evaluated using specialized instruments based on the photoelastic effect. However, these high-precision instruments are expensive, have slow testing speeds, and restrict the resolution and aperture size. In this paper, we propose an efficient method to achieve a high-resolution polarization error test of large aperture optical material quickly. The polarization-tunable test optical path was modeled using the Jones matrix, and a detailed mathematical analysis was provided based on this model. To validate the method's feasibility, experiments were conducted using a Fizeau interferometer to test a flat optical element with an effective diameter of 230 mm. The results were compared with those obtained from commercial instruments, demonstrating consistency between the two methods and achieving a repeatability of 0.1 nm/cm in the peak-to-valley (PV) value with a standard deviation of 0.029 nm/cm. This method represents a substantial advancement in polarization error testing, as a guide, a Φ200 mm synthetic quartz achieves a phase delay of residual birefringence better than 0.32 nm/cm. Thus, the result demonstrates the method's potential in facilitating the achievement of ultra-high precision optical systems.